The Easter getaway is expected to peak on Thursday with 86,000 people taking flights with British Airways.
The airline says 80,000 passengers a day are booked to fly over the extended holiday period from yesterday (Monday).
Flights will reach their peak on Thursday at airports such as Heathrow, Gatwick and London City.
The US is the airline’s most popular long haul destination, with New York, Los Angeles, Miami, Boston, Chicago and San Francisco topping the list.
Other favourites include Dubai, Johannesburg and Delhi.
Top European destinations are Barcelona, Rome, Geneva, Berlin, Paris, Munich and Amsterdam, while busy domestic routes are from London to Edinburgh, Glasgow and Manchester.
BA says it has been gearing up for a busy weekend in anticipation of “massive numbers” of travellers.
Head of UK and Ireland sales Richard Tams said: “We know how important the Easter getaway is for families and other travellers wanting to escape for the holidays and we’ll do all that we can to ensure they’ve a great start to their trips.
“Most of our flights are very busy as our key destinations are proving as popular as ever, especially to the US and top Continental hotspots.”