Sir Richard Branson is supporting calls from airlines for the non-stop Gatwick Express rail service to be saved.
Sir Richard Branson wants the Gatwick Express to stay as it is
It is set to be axed as part of an overhaul of the congested main line route between Brighton and London.
Sir Richard, backing BAA's Save the Gatwick Express campaign, said: "It needs to remain as a dedicated, non-stop and frequent service."
The Department for Transport (DfT) said a decision was due to be announced on its Brighton main line review.
A three-month consultation into the proposals ended on 22 December.
The end of the Gatwick Express was announced last February, with the government's Route Utilisation Strategy then putting forward four future options for the line from Brighton to London.
The plans aim to cut overcrowding between Brighton and London
Three of them would retain a modified, non-stop Gatwick service, but it would be open to commuters as well as airport travellers.
BAA said its campaign was being supported by, among others, Continental Airlines, Virgin Atlantic, British Airways and easyJet.
The airports operator said 80% of respondents to an online poll had supported the full retention of the Gatwick Express.
Sir Richard said the service would be needed when the Olympic Games come to London in 2012.
"Gatwick Airport will become a key arrival point for thousands of spectators, and they will need the most efficient and integrated transport interchange to connect, by public transport, into London," he said.
A DfT spokesman said: "We will now take forward implementation of the strategy working with industry partners, and a decision will be announced in due course."