There must be a new minimum distance between seats on UK airlines in order to ensure passenger health and safety, an influential report says.
Many UK airlines already meet or surpass the Lords' recommendations
The House of Lords Science and Technology Committee says limited space on some carriers may stop passengers properly adopting the brace position.
It is also concerned about the risk of blood clots in more cramped seating.
Most UK airlines meet the Lords' recommended 30" (76 cm) pitch. Others, including Easyjet, do not on all seats.
Seat pitch is the distance between the back of one seat and the back of the seat behind.
A spokeswoman for Monarch, the majority of whose seats on short haul flights are 29" (73.7cm), said the airline would be "evaluating the recommendations", but stressed that roomier seats were available for a small fee.
The House of Lord committee also said it wanted airlines to ensure pilots had appropriate rest periods, following reports from the unions that the schedules of those working for low-cost airlines may be putting lives at risk.
"Air-crew occupational health has featured heavily in our report," said Lord Patel, who took part in the inquiry.
The panel also said there was not as yet adequate scientific evidence to prove a link between contaminated air on flights and long-term ill health, but it did stress there needed to be thorough research into the issue.
But it said action was needed on seat distances, calling on the Civil Aviation Authority (CAA) to increase the minimum seat pitch to 30".
This is primarily due to the committee's concerns about passengers not being able to adopt the brace position in a crash landing, but fears about deep vein thrombosis (DVT) also played a role.
Blood clots can form in the lower limbs during long periods of immobility - and can kill if they travel to the lungs - although the risk of this remains low.
The minimum distance between seats is currently 26" (66cm), which translates into a pitch of about 29", depending on the type of seat.
But the CAA said it did not hold responsibility for this, and that any changes to minimum distance had to be made at a pan-European level by the European Aviation Safety Agency (EASA).
The committee did in fact also raise concerns about the number of CAA health responsibilities which have been transferred to the EASA, arguing that until the European body had proved itself "competent", those powers should remain with the CAA.
It also criticised the government for taxing premium economy services on long haul flights at the same rate as first class travel.
"It points out that premium economy was intended to represent a small extra charge to guarantee leg room to those who require it.
"The committee feels that an extra tax on those who have a medical need for extra leg room is unfair."
A spokeswoman for EASA said it was looking into the report, but that it primarily saw seat distance as one of comfort, and only one of safety in terms of how quickly an aircraft could be evacuated.