Abta is advising travellers to allow more time to clear security checks, as it predicts that more than two million British holidaymakers will head overseas for Easter.
Many UK airports and Eurostar have increased security patrols and enhanced security checks following the attacks in Brussels on Tuesday.
Abta has encouraged holidaymakers to allow adequate time for check in at airports.
More than 425,000 travellers will depart from Heathrow for an Easter getaway, while Gatwick is reporting record-breaking figures of 290,000. A further 157,000 will leave from Stansted and another 80,500 from Luton.
Airports in the rest of the country will also see large passenger numbers, with 59,000 departing from Birmingham, 36,000 from the East Midlands, 17,500 from Newcastle and 200,000 from Manchester.
Eurostar is expecting more than 22,000 people to depart from the UK on Good Friday alone.
In a statement, Abta said: “This is expected to be a particularly busy Easter for holidays. Spain is once again the most popular destination for the Easter break with the Canary Islands in particular seeing large numbers of British holidaymakers.
“Further afield, Orlando, Dubai, Mexico and the Dominican Republic are popular choices. Holidaymakers are also expected to take advantage of the early Easter and hit the ski slopes. Geneva airport is expected to be very busy as skiers head to the Swiss, French and Italian Alps.”
Thomson and First Choice said they had nearly 10,000 more customers setting off for Easter compared to last year. The operator said Cape Verde was the stand out destination, with year-on-year bookings up 59% to the islands. Thailand has also seen an uplift, with 26% more bookings year-on-year.
Andrew Flintham, commercial director for Thomson and First Choice, said: “Florida has always been a family favourite for the Easter break, but this year we are seeing record demand for exotic destinations like Thailand as Brits look to escape to the sunshine and experience a different culture.
“Over the last few years we’ve seen significant growth in long-haul holidays and we will continue to expand into new, far-flung destinations to meet this demand.