Reporting to BA head of corporate communications Iain Burns, Marston, 49, will co-ordinate the airline's global media strategy, consumer and corporate news, as well as crisis comms.
'We get 63,000 press calls a year, and that's just the reactive work,' Burns said of the 24-hour news operation.
Marston fills the role vacated by Steve Double, who left BA last September to become head of media comms at Cable & Wireless.
Marston's appointment comes hot on the heels of the announcement that former Aer Lingus chief executive Willie Walsh will succeed BA chief Rod Eddington from September.
Last year's media storm surrounding flight cancellations and staffing problems has died down, but Burns said there were plenty of issues for Marston, who joined this week, to tackle.
Burns nominated Heathrow's third runway - set to open in 2015 - ongoing environmental issues and the threat posed by low-cost airlines as some of BA's comms challenges.
Marston has almost 30 years of journalism experience. He joined The Daily Telegraph in 1987 as education correspondent before moving to transport in 1996. He was previously political correspondent at The Press Association.
Burns said: 'I was simply looking for the best person for the job but the fact that Paul brings so much Fleet Street experience will be hugely helpful. He is extremely well known among journalists on the BA beat.'
Marston will lead a Heathrow-based team of six press officers, including his deputy, Amanda Poole.