Tui is still planning for a 17 May resumption of international travel.
Last week, the government set out its plans for a traffic light system to govern a likely limited restart, which remains fixed for 17 May "at the very earliest".
This will see destinations sorted into Green, Amber and Red categories, dictating what testing and quarantine rules travellers returning from individual countries must abide by.
Jet2.com and Jet2holidays chief Steve Heapy said he was disappointed with the scope of the Global Travel Taskforce’s review, published on Friday (9 April).
The airline and operator has since cancelled all flight and holiday departures up to and on 23 June.
Tui, though, plans to go ahead with its programme – where possible – from 17 May.
"We don’t have any plans on pushing back our start date," said a spokesperson.
"We’ve offered our customers maximum flexibility by allowing them to amend if they want some certainty, but most customers are still hopeful, like us, that we’ll be flying from 17 May."