About 2 hours
Most would fly into either London Heathrow or Gatwick Airport.
London Heathrow Airport and London Gatwick airport.
10 hours
Heathrow is the nearest airport
It takes approximately 1 hour 50 minutes to fly from Heathrow to Austria.
From LAX (Los Angeles International Airport) flying directly to LHR (London Heathrow Airport) is a flight of about ten and a half hours.
The flight time from London Heathrow (LHR) to Tribhuvan International Airport (KTM) is 9 hours, 10 minutes.
About 9 hours
This depends as London has 5 airports servicing it. Generally speaking, although probably the furthest away, Luton Airport is the cheapest to fly into and Heathrow would be the most expensive.
Fly Aeroflot from Moscow Sheremetyevo Airport to London Heathrow, then Virgin Atlantic from London Heathrow to Miami, Florida, USA.
Gatwick, because it is less often used annually and it is smaller than Heathrow.