germany – Should I follow COVID restrictions for the destination country only or also the layover country?


United States -> Germany (layover) -> Spain


Spain -> Germany (layover) -> United States

I’m a US citizen traveling from USA to Spain this October. The flight has a layover in Germany. Do I only need to follow the travel restrictions for my final destination (Spain) or do I also need to follow the restrictions for my layover (Germany)?

Luckily, both Spain and Germany have the same requirements of proof of vaccination or negative COVID test. However, they differ in the website/app you need to use to upload the documents. Do I need to follow all steps for Germany or can I just do Spain?

Additionally, for Spain, am I supposed to be following the Spanish-USA embassy’s rules or the Spanish-German embassy rules?


Effective September 6, 2021, U.S. citizens can travel from the United States to Spain on non-essential travel, such as tourism) if they show proof of vaccination. Please read the detailed information on the Spain Ministry of Health’s website. Additionally, travelers from the United States to Spain must present a QR code generated through the Spain Travel Health portal, obtained through the website or by downloading the SpTH app in Google Play or App Store for each traveler. Additionally, travelers must show either proof of vaccination, a negative COVID test, or a certificate of recovery.


Effective August 1, 2021, all travelers ages 12 and older must submit proof of vaccination (with a vaccine listed on this website ), proof of recovery from COVID-19 in the last 6 month, or a negative COVID-19 test in order to enter by air, land, or sea.

Please fill out the digital registration on entry at and carry the confirmation with you when entering the Germany. The confirmation will be checked by the carrier and may also be checked by the Federal Police within the framework of its responsibilities as a border control agency.

covid 19 – Where can one still sail on cruise ships without being vaccinated, with the least possible segregations or restrictions on board?

After those challenging years, cruise lines restart their voyages. Most apply vaccine requirements or give reduced rights & other penalties to Covid-unvaccinated travelers.

In which conditions can an unvaccinated traveller sail as of today and not feel like a second-class citizen on board?

It depends on each cruise line. Furthermore, each line can apply different rules in different parts of the world, surely influenced by local laws such as the recent Bahamas decision. The whole picture is difficult to track.

I had a positive experience with MSC in Europe. They only require a test for boarding if you do not have the vaccine. Everyone gets the nose swab at the terminal. Once on board, there used to be a excursions-only rule to go ashore during port calls. Recently, this rule was relaxed for fully vaccinated travelers, which is the only form of segregation applied. The whole ship is equally accessible without consideration for your vaccination status.

I heard that other lines such as NCL apply “no jab no sail”; Royal Caribbean adds extra charges and restricts access from some parts of the ship. Which is clearly making concerned passengers feel like lower-class citizens.

Note: this is a practical question. To keep the answers constructive, I do not judge this place the appropriate one to debate about pros & cons of the vaccine, personal responsibility, conspiracy theories, etc… Those topics can lead to heated discussions. Let’s keep it focused on practical aspects for someone who has chosen not to vaccinate for multiple possible reasons that are out of the scope of the question, and cannot fall into officially sanctioned “medical exceptions”. To illustrate by an example, extreme pain experienced with medical procedures involving needles could be weighing into the decision.

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Can I travel freely (no COVID-19 restrictions) within Schengen Area after formally entering a Schengen country?

Does this US traveler needed to take any COVID-19 test again

No, testing is not necessary once you are vaccinated in most countries.

to go from Rome to Paris you need to have proof of vaccination although it’s unclear what they will accept and fill out the “Statement of honor” document there.

Paris to Marid? “You must complete the entire Form from the website or the app, and from 48 HOURS before the flight you can send the form to the health authorities. Once sent you will receive an email with a QR Code that will allow you to access the destination airport. You must have it printed or on your mobile phone”.

Or he/she can travel freely without having to do anything?


differential equations – DSolve skips restrictions when expressing the solution from the first integral

I consider the ODE: $$y’ =-frac{y^2+1}{x^2+1},$$
and DSolve

DSolve({y'(x) (x^2 + 1) == -(y(x)^2 + 1)}, y(x), x, 
 Assumptions -> Element(x, Reals))

gives the solution $y=y(x)$:

{{y(x) -> -Tan(ArcTan(x) - C(1))}}.

But, if I solve the equation by the separable variable method, then I get the general solution in the form
I can express the solution from this equation in the form of DSolve answer, but I have restriction $ – pi/2 < C-arctan(x) < pi/2$.
Of course, Reduce gives this resuts:

Reduce(ArcTan(y) + ArcTan(x) == c, y, Reals)

1/2 (2 c - Pi) < ArcTan(x) < 1/2 (2 c + Pi) && 
 y == Tan(c - ArcTan(x))

but DSolve does not show it.

What is the reason for this?
Is there any possibility to influence on DSolve?

Current travel restrictions from Germany to France (and return) via Amsterdam on KLM

I would like to understand the regulations and restrictions for an Indian national with German temporary residence (expiring at the end of this year), who has been fully vaccinated in Germany more than 14 days ago, and has a EU Digital Covid Vaccination Certificate. The intended journey dates are later this month. I am listing my current understanding below, and would appreciate feedback in case I have missed something:

  1. Germany – Netherlands (transit): Germany is designated as a safe country by the Netherlands, and no proof of vaccination, recovery or negative test is required.
  2. Netherlands – France: Germany and Netherlands are both designated as “green list” by France, proof of vaccination and a sworn declaration are required – since this is a requirement of the destination, it would be required to board the flight in Germany. Quarantine or tests not required.
  3. France – Netherlands (transit): The Netherlands designates France as a “high risk area”. This journey is allowed but only proof of vaccination is required, no tests.
  4. Netherlands – Germany: The part of France where this journey originates is classified by Germany as a “high risk area”, and as per information here, the traveller must complete the Digital Entry Registration and submit proof of vaccination, but no testing or quarantine is necessary. As before, Entry Registration must be completed before boarding the flight in France.

Have I missed anything?

air travel – Can I change planes to transit via the USA, when I am not allowed to enter it for non-essential reasons due to covid restrictions?

To answer the question, as others have said, No, you generally can’t do international-to-international transit in the U.S. without clearing entry immigration inspection and, thus, entering the United States. (There have existed a handful of narrow exceptions to this over the years, such as for passengers continuing on a fifth-freedom flight to another third country on the same aircraft, but these are relatively rare special cases.)

Why is the U.S. different from most other countries in this regard?

U.S. airports (generally) have no sterile (from an immigration standpoint) departures area. Anyone in the area from which flights depart can simply leave the airport without any sort of checkpoint whatsoever. The reason for this is that domestic-to-international connecting passengers are far more common in the U.S. than international-to-international ones. This is mostly because of how large the U.S. is (by both geography and population) and how far from other countries most of it is.

For domestic-to-international connections, the U.S. setup is actually much more efficient. You can walk off of a domestic flight within the U.S. and walk right onto a departing international flight without going through any sort of checkpoint whatsoever (immigration, customs, security, or otherwise.) Indeed, domestic and international flights frequently depart from the exact same gates. There is no exit immigration control in the U.S. You just show your passport as you’re boarding the departing flight and the airline sends the manifest to immigration. This is great for domestic-to-international connections, making them very easy for passengers. It’s also great for departing passengers in general, as they can access all of the restaurants, lounges, shops, etc. in the terminal regardless of whether their flight is domestic or international.

However, the fact that domestic flights arrive and depart from the same area that international flights leave from means that that area is necessarily inside the country from an immigration standpoint, not outside it like in countries that have exit immigration control and sterile international departures halls. Thus, you have to have already been legally admitted to the U.S. to access that area.

Unfortunately, countries essentially have a choice of inconveniencing domestic-to-international passengers or inconveniencing international-to-international passengers. The large international airports in most countries choose the former because most countries are much smaller than the U.S. and/or are located much more closely to other populous countries than the U.S., thus have a much larger share of international-to-international connecting passengers vs. domestic-to-international ones. However, the situation in the U.S. is quite the opposite with far more domestic-to-international passengers than international-to-international ones, so the opposite choice is made.

Additional Benefit: Preclearance Facilities

As a side note, the setup in the U.S. also enables a convenient feature for passengers flying to the U.S.: immigration pre-clearance facilities located in other countries. Most major airports in Canada and several other airports around the world that have a significant number of flights to the U.S. have U.S. immigration facilities on-site, allowing passengers departing on flights to the U.S. to clear U.S. immigration control before boarding. Their flights then arrive in the U.S. as if they were domestic flights, allowing passengers to immediately board other flights or exit the airport with no further immigration, customs, or security controls.

Aside from passengers not having to stand around in more queues after arriving, this also has another very convenient benefit: airports with preclearance facilities can have flights to U.S. airports that don’t have immigration control facilities at all or outside of the operating hours for those facilities, enabling non-stop flights between major airports in places like Canada and the Caribbean to small/medium market U.S. airports.

Such a program would not be possible if the flights might include passengers planning onward connections to a third country without authorization to enter the U.S.

international travel – Currency restrictions on entry/exit to Norway

You are not entering Norway, so you are not subject to any currency restrictions; however you will be crossing into Schengen so you’ll pass through immigration.

However, to combat money laundering any combination of currency that is in excess of EUR 10,000 (when converted) should be declared at your final destination.

If you do not declare it and are caught later, you may end up forfeiting the entire amount (not just the value greater than 10,000 EUR).

The relevant regulation (PDF) has the following to state about it:

Any natural person entering or leaving the Community and carrying cash
of a value of EUR 10 000 or more shall declare that sum to the
competent authorities of the Member State through which he is entering
or leaving the Community in accordance with this Regulation. The
obligation to declare shall not have been fulfilled if the information
provided is incorrect or incomplete.


‘cash’ means: (a) bearer-negotiable instruments including monetary
instruments in bearer form such as travellers cheques, negotiable
instruments (including cheques, promissory notes and money orders)
that are either in bearer form, endorsed without restriction, made out
to a fictitious payee, or otherwise in such form that title thereto
passes upon delivery and incomplete instruments (including cheques,
promissory notes and money orders) signed, but with the payee’s name
omitted; (b) currency (banknotes and coins that are in circulation as
a medium of exchange).

transit – Can I change planes in the USA, when I am not allowed to enter it for non-essential reasons due to covid restrictions?

The US has never generally disallowed entry by air for non-essential reasons. Only entry by land to the US is limited to essential travel (the current order is here for the Canadian border and here for the Mexican border). Foreign tourists are now able to (and have been able to any time during the COVID-19 pandemic) enter the US by air, as long as they have not been physically present in Mainland China, Iran, the Schengen Area, the UK, Ireland, Brazil, South Africa, or India in the previous 14 days, and get a negative COVID-19 test within 72 hours of boarding the flight.

You have not mentioned where you have been present in the last 14 days. You only said that you are a Dutch citizen, but there is no ban based on nationality. If you are a Dutch citizen who has not been in one of the above geographical areas in the past 14 days (or will spend 14 days in a country not in one of the above areas before going to the US), you can get a COVID-19 test and fly to the US to visit or transit with no problem. However, if you will have been in one of the above geographical areas (including in the Netherlands, which is in the Schengen Area) in the 14 days before traveling to the US, you cannot enter the US as a nonimmigrant right now unless you fall into one of the exceptions in the ban (and the exceptions are much more narrow than “essential reasons”). See for example the Schengen Area ban for more details on the exceptions. There are some additional exceptions mentioned here.)

Transiting the US always requires immediately entering the US for immigration purposes, even if you do not leave the airport. If you are unable to enter the US, you are unable to transit the US.