Flight delays that stranded scores of passengers for more than 10 hours at Domodedovo Airport this week were caused by mechanical problems with their aircraft, federal authorities said.
Flights operated by the airlines Kolavia and Yamal faced massive delays Thursday that prompted the Russian Union of Travel Industry to suggest that the airlines had overbooked their flights amid strong holiday sales.
But the Federal Air Transport Agency said the problem was that the planes themselves had not passed the necessary preflight checks to be declared airworthy, Prime news agency reported.
The affected flights were taking vacationers from the Moscow airport to resort towns in Egypt and Turkey.
Complicating matters, passenger traffic jumped by at least 10 percent this week, when the country shuts down for the extended May Day holiday, the Federal Air Transport Agency said.
It said delayed passengers had been provided with food, water and, if necessary, hotel rooms by their airlines.
No more delays were reported Friday. But additional delays could hit all three Moscow airports as the Air Force carries out practice flights for the Victory Day parade on Red Square on May 9.