American Airlines and Delta Air Lines on Wednesday each reported quarterly losses exceeding $1bn, as both carriers wrote down goodwill, aircraft and other assets devalued by a brutal industrywide downturn.

A relentless surge in jet fuel prices and ebbing demand for air travel have forced carriers to cancel routes, slash jobs, retire aircraft and unveil new fees. Struggling to keep pace with the increase in fuel costs, US airlines are lining up as much financing as possible to avert bankruptcy.