The probe will examine situations where airlines continued to operate flights despite people being unable to lawfully travel for non-essential purposes, such as during England’s second national lockdown in November.
The authority said it was aware that in some cases where flights were not cancelled, passengers were still not offered refunds even though they couldn’t travel and were instead offer the option to rebook or a voucher.
"The CMA recognises the airlines sector, like many others, is under strain due to the pandemic," said the authority in a statement issued on Wednesday (16 December).