Aer Lingus claims delays in publishing which countries will have air bridges to Ireland will stop any tourist or business passengers coming here for at least the next month.
Government officials are compiling a "green list" of routes with unrestricted travel to Ireland, which is due before July 9.
From then, anyone returning from a so-called green area won't have to quarantine for two weeks.
The list will be updated every fortnight, and countries with a second Covid-19 wave will be removed from it.
Donal Moriarty, Aer Lingus' chief corporate affairs officer, says the lack of information about the plans will harm the economy:
"Not providing the list of 'green' countries or the criteria selecting those countries until July 9 is a significant problem," he said.
"Inbound tourists or business travellers won't know until July 9 whether they have to quarantine or not and therefore they won't come, they simply won't book.
"Unfortunately, that will have a very negative impact on SMEs and jobs across the economy," Mr Moriarty added.