135km
If you mean Prestwick Airport, there is a rail link from the airport to Central Station. If you mean the town Prestwick, Prestwick Railway Station is on the same line as the airport station and travels to Central Station as well.
I guess you mean from Frankfurt Airport to Frankfurt-Hahn Airport. There is no train to Hahn Airport, but a bus line.
The nearest airport to Boston University is Logan Airport. You can get there by taking the Green Line from BU to Government Center, transferring to the Blue Line (go downstairs) and getting off at the Airport stop.
Take the train from Cardiff Central to London Paddington, take the Circle Line to Victoria station, and catch the Gatwick Express to Gatwick Airport.
Heathrow Airport is the largest and busiest, and one of the busiest airports in the world. It is also the world's busiest airport by the number of international passengers. It is located in the western suburbs of London within the city boundaries and is connected directly to the London Underground (Piccadilly Line). There is also a Heathrow Express - a fast train that goes straight to Paddington station. Gatwick Airport is the second largest - it's also the busiest single-runway airport in the world. It is located directly south of London in Sussex near the large town of Crawley, but is closer to the minor town of Horley. It is located on the main line from London to Brighton and is connected to the city by the Gatwick Express. Stansted Airport is located northeast of London near the town of Bishop's Stortford, Essex. It is connected to central London by the Stansted Express. Luton Airport is located northwest of London in the town of Luton, Bedfordshire. The nearby railway station is connected to London by Thameslink trains. City Airport is located in the eastern suburbs of London. It is connected to the Docklands Light Railway and serves mainly business flights.
The nearest major airport is London Luton Airport (LTN / EGGW). This airport has international and domestic flights from London, United Kingdom and is about 26 miles (straight line) from STN.
Mexico City International Airport in Mexico City, Mexico
Heathrow
Take the East Coast main line train to King's Cross, then get the Piccadilly Line train to Heathrow Airport.
On the MBTA Blue Line, the station called "Airport" is located near Terminal E of Boston' Logan Airport. A shuttle bus will transport people to and from the airport from the MBTA subway station.
You will have to take the Piccadilly underground into central London and change on to the main line for Hoddesdon Herts.
A straight-line flight from Fort Lauderdale / Hollywood International Airport (FLL) to San Francisco International Airport (SFO) is 2,580.6 miles. The drive is 3,034.2 miles.