Abta estimates that 1.9 million people will be travelling overseas over the August 28-31 period.
Top destinations include Spain, Portugal and Turkey, while Madrid, Rome, Amsterdam, Paris and New York are the most popular city break destinations.
More than 550,000 passengers are expected to depart from Heathrow, 270,000 from Gatwick, 145,000 from Stansted and 87,000 from Luton.
A further 175,000 are due to fly from Manchester, 73,000 from Birmingham, 50,000 from Bristol and 150,000 will be leaving from Scottish airports.
Hundreds of thousands will also be leaving the country from other regional airports, ports and the Channel Tunnel. Eurostar is expected to be busy with 75,000 people set to take a late summer break in France.
Abta members also report strong sales to domestic beach resorts and the Channel Islands together with UK city breaks.
Chief executive, Mark Tanzer, said: “This weekend is always one of the busiest of the year with hundreds of thousands taking advantage of the long bank holiday weekend to head overseas for some guaranteed sunshine, or to enjoy the UK’s beautiful countryside and vibrant cities.
“With the pound still high against the euro many Brits will be taking advantage of cheaper prices in the eurozone resorts.”