Monarch marked 20 years of flights between Luton and Gibraltar on Friday.
The airline, which started operating the route in May 1997, has carried more than 1.5 million passengers.
This service is one of Monarch’s longest operating scheduled routes.
The also serves Gibraltar from Birmingham, Gatwick and Manchester airports running a total of 18 weekly departures this summer, offering about 190,000 return seats.
Monarch chief operating officer, Ian Chambers, said: “We are delighted to be celebrating 20 years of flying to Gibraltar.
“Monarch is the airline with the most routes between Gibraltar and the UK, flying from four of our five UK bases.
“It’s a popular route for us which has grown steadily during the last two decades and as a result of a recent increase in demand we have added frequency into our Manchester programme for summer 2017.
“The Gibraltar routes are part of our core network and we are proud to have flown more than one and a half million customers since the route first started in 1997. We are looking forward to the next 20 years flying to this fantastic destination.”