Airlines are being advised to make sure they have records of all correspondence with delayed passengers in light of the Thomson v Dawson case earlier this week.
Law firm Thomas Eggar LLP said all historic information relating to possible claims need to be properly stored and retained as the industry is likely to face an increase in claims.
The law firm also warned airlines to make sure they have details about the length and reason for all flight delays over the past six years.
"This may mean proactively contacting ex-employees to obtain this information if it is not already on file," said Thomas Eggar solicitor Stephanie Beckett.
The warning came as a court decided that passengers have up to six years to make a compensation claim for a delay of more than three hours.
Thomson has said it will appeal against the decision, claiming two years is long enough.
"Passengers and airlines alike should keep a close eye on how this case develops in the coming weeks as, if this ruling is left unchallenged, it will have far-reaching consequences for the levels of compensation paid out for flight delays. This, in turn, will inevitably increase fare prices for passengers," added Beckett.
"This is the Court of Appeal’s second landmark case this month which could have a serious impact on the levels of compensation which airlines pay out for delayed flights, following the ruling in the Jet2 case."
