(Reuters) -Reclining seats are the latest airline perk to come at a cost - and it is irritating both passengers and staff.

Calgary-based WestJet on Wednesday started flying the first of 43 newly configured planes whose standard economy seats come in a fixed position. Reclining seats are still available, but passengers must pay extra, sparking a backlash from some travelers and even pilots, who say the change could affect health and safety.  

Bernie Lewall, chair of the union local representing WestJet pilots, said he wants guarantees that pilots won't be forced to sit in non-reclining seats when flying to work assignments, a practice known as deadheading.

"If they think that there's a market out there I'm ok with that," said Lewall, chair of the WestJet ALPA Master Executive Council. "What I'm not ok with is being forced to deadhead in a seat like that where it could potentially lead to health and safety issues, or fatigue issues."

Pilots are considering filing a grievance over the matter, he told Reuters.

WestJet said any deadhead travel for the pilots will be managed in accordance with their collective agreement.

While European low-cost carriers generally don't offer reclining seats, the shift is new to North Americans, who see it as yet another charge for formerly free perks like carry-on baggage and seat selection.

"I think there has to be an alternative to making flights more affordable for the working class without taking away the comforts," said Gurneet Singh, 28, a student from the Greater Toronto area.

Melissa Fisher of Portland, Oregon, said travelers have little power to push back as low-cost carriers increasingly rely on charging for extras to shore up their struggling finances.

"What are you going to do? Not fly? Pay more?" she said.

Not everyone is a fan of reclining seats in economy, regularly the cause of in-air disputes. WestJet said half the passengers who tested the new seats preferred the fixed recline to avoid others encroaching on their space.

The remaining 42 aircraft will be completed early next year, and will make up less than a third of the airline's narrowbody fleet.

"Unfortunately, there's no legal right to reclining seats," added Dr. Gabor Lukacs, founder of the nonprofit group Air Passenger Rights.