The Civil Aviation Authority (CAA) has reminded airlines of their lawful obligation to provide refunds to customers despite the coronavirus pandemic.
Hundreds of scheduled flights out of Britain have been cancelled during the past few weeks, leaving plane operators inundated with refund requests.
Many customers have reported difficulties claiming back their money, with some airlines offering credit vouchers for travel at a later date.
However, the CAA has said consumers should have a "clear option" to obtain a cash refund.
The BBC has reported a statement from the CAA, which reads: "Under the law, consumers are entitled to receive a refund for their cancelled flights, despite the challenges the industry is currently facing.
"We support airlines offering consumers vouchers and rebooking alternatives where it makes sense for the consumer.
"But it is important that consumers are given a clear option to request a cash refund without unnecessary barriers."
The law states that passengers must have their tickets refunded within seven days if the flight is cancelled.
Whilst the pandemic is creating a challenge for plane operators to respond to long queues of customer complaints, the CAA has warned airlines it will take action "to ensure that consumer rights are protected."
The travel industry continues to struggle in the current climate, with many major airlines cutting jobs and some even going into administration - such as Flybe.
During a televised address on Sunday, Prime Minister Boris Johnson also confirmed a 14-day quarantine period for people arriving in the UK from other nations.
This will be commencing from the end of May.