Simplify the following text for a Grade 10 native English-speaking person.
Original: In 2010 London City was the fifth busiest airport in terms of passengers and aircraft movements serving the London area after Heathrow , Gatwick , Stansted and Luton and the 14th busiest in the UK .
Simplified: London City is the fifth-largest international airport in size serving the London area after Heathrow , Gatwick , Stansted and Luton .