EasyJet had said it will not add surcharges to pre-booked flights or package holidays, or any new bookings for summer 2026.
The group stressed it was not currently experiencing any disruption to its supply of jet fuel, adding all its flights and package holidays were continuing to operate normally.
Similarly, Tui managing director UK and Ireland Neil Swanson said the airline and operator not add fuel surcharges this summer.
By contrast, British Airways parent IAG said it would make price adjustments to reflect higher fuel costs, stressing it was "not immune" to the effects of the war in Iran.
Earlier this month, easyJet said it had incurred £25 million in additional fuel costs over the winter, while Tui has disclosed a €40 million hit owing to the war.
The government has relaxed airport slot rules to give carriers some respite, which could see them pause less profitable routes to preserve fuel supplies.
Brent oil prices rose again at the weekend to $107 (£79) a barrel after a second round of peace talks between the US and Iran stalled. It means the Strait of Hormuz remains shut, which is limiting the flow of oil out of the Gulf region, and by extension, supplies to be refined into jet fuel.
Jet2's decision not to introduce fuel surcharges this summer came hours after a plea from Deben Travel owner Lee Hunt who, speaking to TTG, called on travel's major operators to come out and publicly lay to rest any suggestion they will add surcharges while the war in Iran constrains supplies.
"We need some really positive messaging from these big companies, which we don't seem to be getting," said Hunt.
'Absolute peace of mind'
EasyJet holidays and Tui's decisions to rule out fuel surcharges means the UK's three largest Atol tour operators, together accounting for 16.5 million Atol authorisations – around half of total capacity – have all committed not to introduce surcharges.
EasyJet said its decision would reinforce it and its in-house operator's commitment to "transparent pricing". It added all holidays this summer would be backed by its Best Price Guarantee and Ultimate Flexibility policy.
"We know holidaymakers may have questions about what recent global events might mean for their travel plans this summer so we are giving our customers absolute peace of mind that no surcharges will be added to their flights or package holidays," said easyJet holidays chief executive Garry Wilson.
"Our operations remain unaffected, so customers can be confident that not only will their holiday go ahead as planned, but there will be no surprise extra payments."
Swanson added: “We understand that customers want both confidence and clarity when booking a holiday. Our teams are here to support people who are thinking about booking, and those who have already booked with TUI can be reassured that their holiday price is fixed, with no fuel surcharges added.”
Slot rules relaxed
An IAG spokesperson said that while the group, which also owns Iberia, Aer Lingus and Vueling, was not currently experiencing interruptions to fuel supply and had hedged its supply, fuel prices had "risen sharply".
The spokesperson added the group welcomed a move by the UK government to relax the 80:20 "use it or lose it" slot rule, meaning airlines won't be required to use 80% of their allocated take off and landing slots during a season to retain them the following year.
The Department for Transport has confirmed Airport Coordination Limited, the independent body that manages slot allocation at UK airports, has updated its guidance to ensure airlines won't lose their slots if fuel shortages prevent them from flying.
"Airlines can now apply for an exemption from the 'use it or lose it' rule in these circumstances," said the DfT. "This means airlines can focus on minimising disruption for passengers, rather than feeling pressure to operate flights purely to protect their slots."
