During the Lon Nol period, air travel played an essential role because most of the roads to many provinces were cut off into liberated zones under the control of the Khmer Rouge. The Khmer Republic government, backed by the United States, transported supplies, especially food, via plane to and from Pochentong Airport.

Although the government of the Democratic Kampuchea cut off the relations with most of the world, air travel was still happening between 1975 and 1979. Often, Pochentong Airport received many Chinese advisors that traveled to Cambodia who were providing training for Khmer Rouge cadres. In mid-1975 and 1976, there were Cambodian intellectuals and diplomats of the National United Front of Kampuchea who volunteered to come back to Cambodia. They had to travel to Beijing in order to take the only flight going directly to Phnom Penh.