British Airways and Iberia parent IAG announced Thursday that a takeover bid for Aer Lingus had been rejected by the board of the Irish flag carrier.

Shares in Aer Lingus leaped 14 percent earlier in the day after the Financial Times disclosed BA was weighing a bid. IAG said: "There can be no certainty that any further proposal or offer will be forthcoming." Aer Lingus is the third-largest carrier at London Heathrow, BA's home airport, where few take-off and landing slots are available. Both the Irish government and Ryanair own significant stakes in Aer Lingus.