Travellers stranded abroad by the volcanic ash cloud returned to the UK in a trickle rather than a flood as recriminations flew about the Government's handling of the crisis.
All UK airports reopened but many services were cancelled, with budget airline Ryanair unable to operate any flights at all.
A leading holiday company chief said the Government's response to the crisis had been "a shambles", while Conservative leader David Cameron accused ministers of "muddle and confusion".
Liberal Democrat leader Nick Clegg, whose three young sons were stranded in Spain, said there would have to be a "post-mortem" of the response to the crisis.
But as returning passengers spoke of how they "despaired" of ever getting home, Prime Minister Gordon Brown defended the time taken to reopen UK airspace, stressing that passengers had to be "safe and secure".
He added that the Government would never have been forgiven if aircraft had been allowed to fly when people's lives were at risk.
Transport Secretary Lord Adonis denied the decision to reopen UK airspace - made by the Civil Aviation Authority (CAA) last night - had been based on pressure from airlines.
And CAA chief executive Andrew Haines said he "made no apologies" for UK airspace being closed for so long and added that any inquiry into the crisis would support the CAA's actions.
Most carriers were able to run only a limited services, with Ryanair flights not starting again until 1pm Thursday.
