PA Media
The airport said that 20 flights have been cancelled throughout the day on Monday
Gatwick Airport has said operations are "returning to normal" after four days of fog-related flight restrictions.
Temporary air traffic restrictions that were in place over the weekend have been lifted after the weather improved.
More than 20 flights planned for the West Sussex airport on Monday were cancelled in advance to minimise any impact on passengers and allow for repositioning of aircraft.
Flights at the UK's second busiest airport were disrupted between Friday and early on Monday morning because of fog.
Travellers Sam and Alyssia were due to fly into Gatwick from Sweden on Sunday but received a text message from their airline three hours before take-off, telling them their flight had been cancelled.
"I don't really understand why they cancelled it because of the fog," said Sam.
"I've seen planes having to fly through storms before, and they've still been able to land.
"When we looked into it, it was only certain flights that had been cancelled by that airline, so it was a really big inconvenience for us when that happened."
Sam and Alyssia's journey from Sweden to Gatwick took 16 hours longer than expected
The pair eventually arrived at Gatwick some 16 hours after they had been scheduled to.
A spokesperson for Gatwick apologised for the delays and cancellations.
An easyJet spokesperson added: "Unfortunately, a small number of flights this morning to and from London Gatwick were cancelled due to the knock-on impact of air traffic control restrictions from poor weather conditions yesterday.
"The safety and well-being of our customers and crew is our highest priority, and while this is outside of our control, we would like to apologise to customers for the inconvenience caused."
Anyone on flights delayed by more than two hours may be entitled to assistance, including food and drink or overnight accommodation if necessary.
At Gatwick on Sunday, around 30 departures and 28 arrivals were cancelled throughout the day
The weather at Gatwick on Monday morning was overcast.
There is no fog forecasted throughout the day, and a dry, breezy and mild day is anticipated.
It is expected to turn into cloud later in the evening.
When the fog dissipates, many planes and pilots may be out of place due to the previous delays and cancellations, which is likely to bring further disruption to air travel.
Air traffic control provider Nats said in a statement: "The weather conditions that caused disruption to UK airports over the weekend have significantly improved.
"Only a few air traffic regulations remain, and these are within normal operating limits.
"Passengers should still check the status of their flight with their airline, as there may be knock-on impacts to the usual flying schedule."
There has been disruption at the UK's busiest airport since Friday, and it lasted over the weekend, when the airport expected its busiest day over the festive period.
At Gatwick on Sunday, around 30 departures and 28 arrivals were cancelled throughout the day.
Other airports around the UK, including Manchester, Glasgow and Cardiff, were among the airports where flights were also disrupted on Friday and Saturday.