People in the UK cannot currently travel to the popular destination of Majorca for holidays, but chief executive of Manchester Airport Group (MAG) has said EU countries were taking a more positive approach to resuming international travel, including Germany.
The boss of Jet2 said also he was "bewildered" that people from the UK couldn't fly to destinations in the Balearic destinations.
The Spanish island of Majorca - which is popular among UK tourists - is currently on the amber list.
This means travel to this destination is not advised and quarantine is required on return to the UK.
However, Covid rates are lower in Majorca than in the UK and in recent weeks, German tourists have started arriving in Majorca in large numbers. German travellers only need a digital pre-registration and either an antigen test or proof of vaccination.
'Hundreds of thousands of people from places like Germany are travelling freely and safely to low-risk holiday destinations'
Palma de Majorca Airport confirmed to the BBC that during May, 397,931 tourists arrived from Germany on 3,363 flights. In contrast, 5,813 UK tourists arrived on 333 flights from UK airports.
Earlier this week, Easyjet announced it was increasing capacity from Germany to Majorca, in order to cope with a rise in demand for holidays to the destination.
Garry Wilson, chief executive of easyJet Holidays, said: "We've just recently added 150,000 seats from Berlin into Palma to try meet the huge pent-up demand that has been released from those restrictions lifting.
"It is a shame we can't do the same for UK customers, because we know demand is there."
Jet2 and Jet2 Holidays' chief executive, Steve Heapy, said: "When you take the UK government's own criteria for deciding where holidaymakers can travel to, and apply it to the Balearics, we are left bewildered as to why we cannot fly there.”
He added: "Other nationalities are going, German customers are arriving on jumbo jets that are being put into Majorca and hotels are filling up.
"Hotels will give rooms in the future to these other nationalities and British tour operators and customers could be squeezed out.”
Charlie Cornish, chief executive of Manchester Airport Group (MAG), also noted that "hundreds of thousands of people from places like Germany are travelling freely and safely to low-risk holiday destinations.”
A Department for Transport spokesperson said: "Our first priority is protecting the public and saving lives, and the traffic light system we have in place categorises countries and territories based on risk, using the latest data.
"As set out in the Global Travel Taskforce, we continue to engage with international partners to explore how we can open international travel safely."