Airlines from outside the SkyTeam alliance will take part in this year’s annual Sustainable Flight Challenge.

The “friendly competition” is in its third year and aims for entrants to develop a solution that airlines can use to be more environmentally friendly and to share that with the industry.

This year low cost Turkish carrier Corendon and mainstream leisure carrier Tui Airways will take part despite not being in the SkyTeam alliance. New member SAS will also take part.

This will take the total number of competitors taking part to 22, including some affiliate members like Transavia. Sky Team has just 19 full airline members.

Partick Roux, SkyTeam chief executive, said: “It’s all about making travel more responsible.

“Having non-Star Team members taking part if a first for leisure carriers and show how seriously the pressing issue of climate change and environmental impact is being taken.

“Using the power of friendly competition we challenge participants to find new solutions and innovations to help reduce flying’s impact at least in the short term.”

Roux said the challenge has already produced 450 ideas that have been shared among participants.

“The focus of this year is to take these ideas and to scale them and to implement them to demonstrate the impact that they can have. It’s about acceleration and implementation.”

Airlines must operate at least one showcase flight in August, September or October and the winners of the challenge will be decided by a judging panel of experts.

Flights are only eligible when the destination cannot be reached by alternative transport options within six hours.

Award categories will recognise airlines with a strong approach to scaling sustainable aviation fuel (SAF), who excel in collaborative efforts and those who focus on embedding sustainability in broader business practices.