The non-stop express rail link between London Victoria and Gatwick Airport is to be axed, the government has said.
Airlines were keen to keep the Gatwick Express high-speed link
The move is designed to reduce overcrowding on services on the route, the main London to Brighton line.
The Department for Transport said "fast and frequent" services would remain but would serve additional stations.
Figures show that during peak morning hours the service is, on average, just over half full. Axing it would provide an extra 480 seats for commuters.
A Gatwick Express spokesman said the future of the service had not been "100% confirmed".
In a statement, transport minister Derek Twigg said there would still be "a high-quality service" for airline travellers.
GUIDE TO THE GATWICK EXPRESS
The service between Gatwick and London Victoria runs on the London-Brighton line
The journey time is 30 minutes, non-stop, and trains depart every 15 minutes
Fares for Express Class Return are currently £25 and £38 for a First Class Return
The rail link to Gatwick opened in 1959 and the Express operation began in 1984
National Express was awarded a 15-year franchise in 1996, bringing in new trains in 2000
A brand overhaul included signage and poster sites at Gatwick and London and uniforms by Paul Costelloe
Mr Twigg said the move had taken into account concerns raised by UK airports operator BAA and airline companies.
Criticisms of the move came from BAA which said air passengers and commuters would have to "tussle" for space and the Board of Airline Representatives in the UK which said air passenger numbers were growing.
But the Rail Passengers Council said it was a "brave attempt" to solve overcrowding problems, while the Strategic Rail Authority, which has since handed over its remit to the DoT, said the plans could benefit everyone.
Mr Twigg said commercial negotiations with train operators about changes to the whole of the Brighton mainline service had begun.
He said one of the proposed improvements had already been introduced - a direct Brighton to Ashford service linking coastal towns with the Brighton main line and the Channel Tunnel Rail Link.
The Gatwick Express brand was overhauled by National Express
The move includes the withdrawal of direct Hastings-London trains via Eastbourne during the day, although direct trains will still run in the mornings and evenings.
Passengers were protesting outside Bexhill rail station on Friday with the Conservative MP for Bexhill and Battle, Gregory Barker.
Bexhill Rail Action group chairman Brian Hord said "a key piece of regional infrastructure between the Hastings/Rother area and Gatwick, Croydon and London is to be lost".
He added: "They calculated, wrongly, that we would take this lying down."