Fog has been causing some problems at the San Luis Obispo County Regional Airport this week.
Airport Assistant Manager Craig Piper says low evening fog has resulted in flight delays, diversions and cancellations. Planes have had to either divert to other airports or return to the airport from which they took off.
The delays have extended to morning flights, as well.
Piper says this is unusual at this time of year.
It comes as the FAA is working to replace equipment at the airport that helps pilots land.
Passengers have expressed frustration at the delays and cancellations, which have caused many people to cancel or rebook their flights.