More than 8,800 flights will leave or enter UK airspace on July 21, making it a record day for British skies.

The day after the schools break up for summer is annually the busiest day for air traffic, but the peak period stretches across July and August. NATS, the UK’s leading provider of air traffic control services, says the UK’s aviation network will handle 770,000 flights this summer, the highest number in its history and a five per cent increase on last year (or 40,000 more flights).

This weekend marks the start of the summer holidays Credit: Getty

NATS says the video above highlights the increasing pressure on British airspace, with a growing potential for congestion around the country’s busiest airports, especially around London.

Forecasts show that UK air traffic will continue to grow from 2.5 million flights in 2017 to 3.1 million by 2030. At the same time the Department of Transport forecasts that by 2030 congestion in the skies will lead to 50 times more delays and 8,000 cancellations a year.

Manchester Airport has already reported its busiest May on record, with 2.5 million people passing through its doors, while NATS said in June it handled one in four of all aircraft to use Europe’s airspace.

Where are all the planes going?

Southampton is set to experience the largest growth this summer, according to NATS, with 14 per cent more flights going in and out of its airport compared to last year, a rise from 12,147 to 13,604.

Belfast International follows closely in second, with a 12 per cent growth for the months of June, July and August, from 12,607 flights to 14,119. Cardiff will see 11 per cent growth this summer.

This weekend, airports in the southeast are expected to be very busy, with more than 500,000 passengers travelling from Heathrow, 335,000 from Gatwick, 136,000 from Stansted and 85,000 from Luton.

Nearly 150,000 are due to depart Manchester, 70,000 from Birmingham and 55,000 from Bristol.

Abta, the travel association, this week said it expects a record 2.4 million people to be heading overseas this weekend, with Spain, including the Balearics and the Canary Islands, Portugal, Greece, Italy and France the most popular destinations. "Abta members are reporting strong growth for Bulgaria and Croatia and significant increases in interest for family-friendly resorts," it added.

It said that Cuba, the Dominican Republic, Jamaica and Mexico have all sold well in the long-haul market but that Florida remains the most popular choice for families.

Which are the UK’s busiest airports?

Based on Civil Aviation Authority data for 2016, Heathrow, one of the busiest airports in the world, welcomes the most passengers in the UK.

Which UK airports are growing fastest?

Keep in mind that some of these airports are much larger than others. Heathrow only registered a one per cent increase.

What does this mean for flights in the future?

More delays, said the Department of Transport. NATS, too, has warned that the UK needs to "modernise" its air space.

The group says that it is spending "in excess of £600 million on new technology" to help boost capacity but argues that investment must be complemented by improvements to the UK's network of flights paths and air routes.

"A shift change shift away from destinations such as Egypt, Turkey and Tunisia in favour of Spain, Italy and the US has also resulted in major changes in the flows of traffic; and with many schools now breaking up, the demand for flying is expected to reach new levels," said NATS.

"A rise in delays would not only inconvenience passengers, but also damage the wider economy. A UK-wide forecast from the Department for Transport shows that by 2030 there will be 3,100 days’ worth of flight delays – 50 times the amount seen in 2015, along with 8,000 cancellations a year."

How many planes are in the sky across the globe?

According to the folk at FlightRadar24, who keep track of aircraft around the world, the number varies based on the time of day and year. “If we’re talking about peak traffic for the whole year, a Friday afternoon between 2pm and 4pm (UTC - coordinated universal time) in July or August will see slightly more than 16,000 flights in the air,” said Ian Petchenik, from the company. “The same time period in January or February will see about 13,000 flights in the air.”

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What are the world's busiest air routes?

Despite the UK's busy summer holiday period putting pressure on Britain's aviation network, it's not a touch on the world's busiest.