British Airways owner IAG is considering mounting a legal challenge to quarantine rules which are due to come into effect on Monday, BBC News reported.
British Airways threatens legal action over quarantine plans
He said he expected other airlines to also mount legal challenges.
"We think it's irrational, we think it's disproportionate and we are giving consideration to a legal challenge to this legislation, so we're reviewing that with the lawyers later on today," Mr Walsh told Sky News.
"I suspect there are other airlines who are doing so, because it's important to point out there was no consultation with the industry prior to enacting this legislation and we do believe it is an irrational piece of legislation."