Egypt is closing its airspace to Qatari planes in a growing diplomatic row, with Saudi Arabia and Bahrain expected to do the same today.
Several countries have cut ties with Qatar, accusing it of supporting terrorism in the Gulf region.
Qatari nationals in Bahrain, Saudi Arabia and the UAE have been given two weeks to leave.
Qatar denies backing militants and its foreign minister has called for “a dialogue of openness and honesty”.
Egypt said it was closing off its airspace to Qatar from 04:00 GMT on Tuesday “until further notice”.
Travel disruption is expected as the airport in Doha, Qatar’s capital, is a major hub for international flight connections.
Airlines affected will include Qatar airways, Etihad Airways and Emirates.