Thousands of EasyJet and Virgin airline staff are being offered work at the new NHS Nightingale Hospital in east London.
Those who sign up will support nurses and clinicians at the coronavirus field hospital, the NHS said.
Virgin Atlantic said furloughed staff who helped would be paid through the government retention scheme.
NHS England said many airline staff were first aid trained and already had security clearance.
The workers would be changing beds and performing other non-clinical tasks and helping doctors and nurses working on the wards, the NHS said.
Two more temporary hospitals are to be built in Birmingham and Manchester and NHS England said other sites were being considered across the UK.
In addition to the hospital in east London, staff at Virgin Atlantic and EasyJet have been invited to volunteer at the sites planned at Birmingham's NEC and the Manchester Central conference centre.
Virgin Atlantic said it had written to about 4,000 employees, while EasyJet said it had contacted 9,000 of its UK-based staff - half of whom are first aid trained.
Travel restrictions and a slump in demand because of the pandemic have forced airlines to cancel most flights and temporarily reduce staff.
Virgin Atlantic cut four-fifths of its flights and has asked staff to take eight weeks of unpaid leave.
News of the voluntary scheme came as EasyJet announced it had grounded its entire fleet because of the coronavirus pandemic.
EasyJet's Tina Milton said cabin crew "could make a real difference".
The number of confirmed coronavirus cases in London has soared well ahead of the rest of the UK, with the capital making up about a third of all deaths linked to the virus.
Last week, the government announced it would turn the ExCeL Centre into a temporary hospital to cope with the surge.
Nearby London City Airport has stopped all commercial flights until further notice and the airfield will be offered to the government "to help with the national effort" against coronavirus.
England's chief nursing officer Ruth May said: "The NHS is mobilising like never before, but the scale of this challenge has not been seen in peacetime so we need all the support we can get.
"Thousands of nurses, medics and other expert staff are returning to work alongside us, but we need everyone to do their bit."
Hundreds of volunteers for the St John Ambulance will also help staff the NHS Nightingale Hospital.
Virgin Atlantic said staff who took up the offer would be given free accommodation and meals.