A record 2.5 million British holidaymakers are set to travel overseas this weekend, with Abta warning of busy transport systems.
Abta says Spain remains the number one destinations for families but reported “strong growth” to Turkey, Egypt, Greece, Bulgaria and Croatia.
In terms of city breaks, popular European destinations include traditional favourites Barcelona, Paris, Rome and Amsterdam.
The association says domestic bookings are “healthy” with travel agents and tour operators reporting demand to the south west of England and seaside resorts in particular.
The majority of schools in England and Wales break up for the summer holidays, with the weekend of July 20-22 the first of the break.
Summer temperatures around Mediterranean hotspots are expected to reach or pass 30C.
More than 500,000 passengers expected to depart from Heathrow, 250,000 from Gatwick, 148,000 from Stansted, 88,000 from Luton and 7,600 from Southend.
Further north, 160,000 are due to depart from Manchester and 67,500 from Birmingham. Scottish schools are already well into their summer holidays, but close to 200,000 are expected to fly from Scottish airports, with 104,000 from Glasgow and 70,000 from Edinburgh.
Other regional airports, ports and the channel tunnel will also be “extremely busy” over the weekend with hundreds of thousands leaving the country, Abta said.
Chief executive Mark Tanzer said: “This weekend is the start of the summer holidays for millions of school children and many families will be flying out to guaranteed sunshine and the opportunity to experience and learn from different people and cultures. Popular destinations in the UK are also expected to welcome holidaymakers and enjoy the ongoing nice weather.
“The roads in the UK will very busy and families should leave a little extra time to get to their departure ports and check for engineering work if using public transport.”