During the third quarter, 24.8 million air passengers were recorded, a big jump on the 6.4 million in the same period in 2020, but still far below normal.
There were 286,842 flights in the third quarter, compared with 126,138 in the second quarter of 2021.
Third quarter figures were lifted by the easing of travel restrictions. In July, it was announced double vaccinated UK citizens would no longer have to self-isolate for 10 days when returning from amber list countries, leading to an immediate rise in passenger travel during the final few weeks of the peak summer period.
Flight delays decreased slightly compared to the same period in 2019, with an average wait of eight minutes compared to six minutes in Q2 2021.
The CAA said: “Following the steady reopening of international leisure travel and recent further relaxation of isolation rules, the outlook for international leisure travel appears positive.
"As a result, we expect further recovery of the number of flights and passengers in quarter four 2021.”