The Lib Dems said the BBC's spending on flights was staggering
The BBC has been accused of being "frivolous" with licence fee-payers' money after it said £10.4m was spent on flights last year.
Of this, £3.1m went on business or first-class tickets, according to figures obtained by the Lib Dems.
Party transport spokesman Norman Baker said the costs were "staggering" and money should not be "splashed around".
A BBC spokesman said spending on flights was "subject to rigorous scrutiny" and had actually fallen.
'Value for money'
Mr Baker, who was given the figures after making a freedom of information request, said: "The BBC's own guidelines say that flying business class should only happen in 'exceptional circumstances'.
"It is hard to believe that there can be £3m worth of exceptional circumstances in a single year.
"Licence fee-payers have a right to assume their money is not being splashed around frivolously. BBC bosses must make sure that, where possible, their staff use trains rather than planes and that when they must fly, they get the best value for money possible."
During 2006/07, the Corporation spent £10.8m, including £2.4m on business and first class.
The BBC spent just under £5m on train tickets last year - about £520,000 of which went on first-class travel. This total for 2006/07 was £4.8m.
A BBC spokesman said: "We reject these [Liberal Democrat] claims completely. Spend on flights is subject to rigorous scrutiny and has actually fallen significantly in the last year, reflecting our commitment to value for money.
"As an international broadcaster, viewers expect us to report stories and bring them programmes from around the world, which inevitably involves travel.
"It is important to make clear this information includes flights by BBC Worldwide, so it is completely misleading to suggest this is all money from the licence fee."