A union is demanding an investigation into suspected toxic gas poisoning of an airline cabin crew.
Two Flybe crew members reportedly collapsed and became violently ill on a flight between Birmingham and George Best Belfast City Airport.
Flybe said all of its aircraft were manufactured and maintained to the highest industry standard.
Dessie Henderson, of the Transport and General Workers' Union, said he had held several meetings with the company.
"They don't seem to be able to find the cause of the problem," he said.
"There has to be a more vigorous investigation into the causes of this, because the bottom line is that the cabin crew and pilots are affected by it."
In a statement, Flybe said: "Any incidents involving sickness experienced by cabin crew, flight crew or passengers are taken very seriously by the company, with appropriate medical support always provided."