Sri Lanka, March 9 -- The Oman base has emerged as the de facto departure point for many of the repatriation flights by European governments but has also been a thriving centre for charter and private planes used by wealthy residents trying to leave the Gulf.

Chartered planes accounted for around a third of flights from the airport over the past week, according to data from Flightradar24.

"Due to the current crisis management measures at Muscat International Airport, flight movements are restricted to approved seasonal scheduled services only," the airport authorities told charter plane operators on Friday, according to an email seen by the FT.

"This measure is necessary to manage congestion and ensure that airport capacity remains...