20 hours Layovers at Heathrow and Dublin airports. Do I require transit visa for both?

I hold an Indian Passport.

I am traveling from Mumbai to Washington DC via the British Airways flight which has two layovers: 16 hours in London and 4 hours in Dublin. I possess an F-1 US student visa. I would be reaching London at 18:25 p.m. and would depart for Dublin at 6:30 a.m. the next day. Similarly, I would reach Dublin at 8:00 a.m. and depart for Washington DC at 12:00 p.m.

I would also need to change terminals at Heathrow from Terminal 5 to Terminal 2.

I wanted to know whether I would require a transit visa for both the places as I am not able to get proper information about the requirements from the official pages. Reading the pages only show that you can transit without a visa if you hold an itinerary to your destination and hold the visa for the US.

Please help me as I am confused and don’t want to get in trouble at international airports.

Transit between airports Singapore Airlines

I am flying from Los Angeles International Airport (LAX) to India NSCBI (CCU) Airport. My flight has two layovers – Tokyo and then Singapore. The different legs of the journey are on the same itinerary. I am flying with Singapore Airlines. I land in Tokyo Haneda Airport at 8 pm and my connecting flight is from Narita International Airport the next day 2:30 am. My question is whether Singapore Airlines would be responsible for my transit as I don’t have a lot of time (six and a half hours not considering checking in, etc.) or do I have to arrange my own transportation?

Is there a list of the most-transited airports in the world?

I’ve seen a lot of lists of the most planes that go through airports, and passenger numbers, but that’s presumably arrive/depart numbers.

What I’m after is what are the airports where the most passengers transit through the airport – ie fly in, don’t leave the airport, and take off again, possibly from a different terminal.

As an example, Atlanta is I gather a big transit airport, as is Singapore or Dubai. However, Queenstown, New Zealand for example, people fly in and out of but do not normally transit, so presumably the numbers would be low.

A top 5/10/20 list would be ideal, or else a link to a database that records this information.

Is it possible to request hand inspection of photographic film in Indian airports?

Per What is the best way to carry photographic film when travelling?, when traveling with photographic film, it’s best to pack it in hand luggage and request hand inspection of undeveloped film.

In the United States, there’s an explicit TSA rule that allows you to request hand inspection of undeveloped film, and in all cases, the security officers will respect that. However, from what I’ve read online, security checkpoints in some countries often insist that one put undeveloped film through the scanners. (While this often results in not much visible effect for lower-speed films, it can be a problem if it’s scanned multiple times, especially when transiting through different countries, and higher-speed films shouldn’t be scanned at all.)

I’ve searched online, but I’ve not been able to find any information on the security rules for India, unlike the U.S. TSA which fully documents its rules online.

Is it possible or easy to request that photographic film be hand inspected at airport security checkpoints in India? Will Indian security officers usually honor the request?

Why is it common in European airports not to display the gate for flights until around 45-90 minutes before departure, unlike other places?

https://youtu.be/wdU1WTBJMl0?t=262 mentions:

00:04:22: Heathrow also doesn’t display the gate for flights until around 45-90 minutes before departure. This is common in European airports, but uncommon elsewhere.

Why is it common in European airports not to display the gate for flights until around 45-90 minutes before departure, unlike other places?

Do I need a transit Visa in one of the airports

I am a Kenyan citizen ,wuld like to travel to Cayman islands from Nairobi through Dubai to Frankfurt using Emirates airlines, from Frankfurt to Panama with a different airline. so will I need any transit Visa in Dubai or in Frankfurt bearing in mind that Kenyans don’t require a visa to Cayman islands and Panama? And if I get to Frankfurt will the airlines check in my luggage to the next flight since I will change the airlines in Frankfurt Germany?

Are airlines responsible for Airport security or Airports concerned or third-parties on terminal-side?

In Indian Airports, all sort of terminal-side security is done by CISF . They do all the frisking and baggage screening etc. I am concerned more for the terminal-side security rather than airside where it comes under the airlines domain.

Is it similar in the rest of the world or are airlines responsible? Some notable incidents I recall are the recent Brussels Airport attack, and the 2015 Sabiha Gökçen Airport bombing. I would suspect most airports now are under some sort of integrated command and control center modeled on the American system after 9/11 rather than have disparate silo-based security which may have holes that both terrorists and criminals may be able to get through.

What food options are available past security in Bangkok airport’s domestic section?

I am flying in from Sweden through Suvarnabhumi onwards to Krabi. Having been in Thailand before, I know how long the lines can be, so I would like to clear immigration, customs and security as soon as possible.

Suvarnabhumi’s website is kind of sketchy on the details as to what food options are available in the domestic part of the terminal. It seems there only something called City Garden, but doesn’t say what kind of venue it is (kiosk, fast food, breakfast, full service, etc).

What are my options? I will be arriving at around 6 AM, so a hearty meal might after the long leg might be in order.

Security check in Turin-Caselle or Malpensa airports

Planning a trip to/from Turin airport (TRN) inside Schengen space. A colleague working there advised about occasional usage of body scanners, whilst the airport contact team states these are not deployed on the airport. This is a sort of draw.

Could anyone (with experience departing from Turin airport) comment on the usage of any kind of body scanner machines there?

Alternatively, experience departing from Malpensa (MXP) airport at Milan -also for body scanners- would help as well.