Flybe Group Plc said American Airlines-backed Mesa Air Group Inc. has launched a counter-bid for its business, leading the stock to more than double in price.

The approach from Phoenix, Arizona-based Mesa and New York private-equity firm Bateleur Capital LLC is "preliminary and highly conditional," Exeter, England-based short-haul carrier Flybe said in a statement on Wednesday, without revealing how much the potential offer might be worth.

Flybe shares surged 131 percent before trading 122 percent higher at 2.89 pence as of 8:35 a.m. in London. A January bid from the Connect Airways consortium of Virgin Atlantic Airways Ltd., Stobart Group Ltd. and Cyrus Capital is worth 1 penny a share, or 2.2 million pounds, though includes a 20 million-pound bridge loan and a commitment to 80 million pounds of further funding.

The proposal from Mesa and Bateleur, which is backed by ex-Stobart chief Andrew Tinkler, would involve a capital injection and replacement of financing that Connect had planned to provide, and is contingent on that deal not going ahead, according to the statement.

Flybe said it's bound by an agreement to sell its operating subsidiaries to Connect and that it has already drawn down funds for payments to credit card companies, meaning the new proposal would not be executable in a time frame that would allow it to survive. Mesa is 10 percent owned by American and provides regional flights for the carrier and United Airlines.

Flybe will hold a special shareholder meeting on March 4 where investor Hosking Partners, which says the Connect bid is too low and that the sale has been mismanaged, may seek to remove Chairman Simon Laffin. The U.K. airline is being squeezed by fuel costs and fare declines on routes that typically link smaller cities where margins are already thin.