A technical issue with air traffic control has led to flight delays at Scotland's main airports.
Edinburgh, Glasgow, Aberdeen and Prestwick airports have been affected by the problem at the Scottish Air Traffic Control centre at Prestwick.
Nats, who provide air traffic control services in the UK, said: "We have had a technical problem overnight with interference on some radio frequencies that we use to speak to aircraft.
"It only affects part of Scottish airspace and flights from some Scottish airports this morning may be delayed as a result.
"We have identified the cause, isolated the problem and the situation is improving.
"We apologise sincerely for any inconvenience."
A spokesman for Edinburgh Airport said: "Due to an ongoing issue at the Scottish Airspace control centre, there will be a delay to all flights this morning. We are still assessing the situation but customers should expect delays."
At Aberdeen Airport a spokesman said a small number of delays were affecting southbound flights but it was hoped they would be back to normal "as soon as possible".
One traveller flying to Paris via Amsterdam tweeted to say they were "stuck on a plane" at Glasgow Airport.
The airport said flights were now beginning to leave but there were some delays. Passengers were asked via Twitter to check their airline for specific flight details.