British Airways owner IAG is reportedly considering re-bidding for Austrian airline Niki.
The development emerged as Lufthansa faces opposition from European competition authorities over its purchase of the bulk of collapsed Air Berlin.
Lufthansa signed a €210 million deal to buy half of the assets of Air Berlin in October, which included the Niki and LG Walter businesses, together with around 20 aircraft.
However, the deal still required approval from competition bodies.
EU regulators have voiced concern over what the bulk purchase would do to ticket prices and competition. Lufthansa owns flag carrier Austrian Airlines.
The European Commission is said to be leaning towards blocking the takeover of Niki specifically, following a meeting on Wednesday between Ms Vestager and Lufthansa chief executive Carsten Spohr.
This came as reports emerged that Lufthansa had been set a deadline of midnight on Thursday to offer competition remedies.
The EU is expected to decide by December 21 whether these remedies are sufficient to grant approval for the purchase.
IAG is thought to be considering resurrecting its earlier offer for the airline amid uncertainty over whether Niki will be back on the market,
Bloomberg, citing a person familiar with the plan, said the bid may be revived if Lufthansa calls off the purchase of Niki due to EU competition concerns, in order to enable the rest of the deal to go ahead.
Earlier this month, IAG chief executive Willie Walsh confirmed the firm had made a bid for Niki, the Daily Telegraph reported.
IAG declined to comment last night.
Speaking to newspaper Frankfurter Allgemeine Zeitung last month, EU competition commissioner Margrethe Vestager warned the Lufthansa-Air Berlin cquisition could create monopolies on some routes.