American Airlines is in early talks to raise cash from Citigroup, its credit card partner, after recently securing a $100m loan from Germany’s DVB Bank, defying mounting scepticism that a major US carrier could lock up additional funding amidst a steepening downturn.

The liquidity comes at a crucial time for American. While slumping fuel prices and steep capacity cuts have helped the world’s second-largest airline and its peers weather falling demand, dwindling financing options have revived concerns that several big carriers are heading for bankruptcy protection.