UPDATE 2-Pilots expand warnings to US airlines on mergers

(Recasts, adds details)

By John Crawley

WASHINGTON, April 15 (Reuters) - Airline pilots unions sharpened their rhetoric on Tuesday as industry consolidation heated up with labor expanding its warning to carriers about trying to merge without their consent.

"The pilots of our respective airlines will not allow any merger unless management meets or exceeds our demands to be treated fairly and equitably," said union leaders at United Airlines, a unit of UAL Corp (UAUA.O: Quote, Profile, Research), and Continental Airlines (CAL.N: Quote, Profile, Research).

The two are said to be considering a merger one day after Delta Air Lines Inc (DAL.N: Quote, Profile, Research) and Northwest Airlines Corp (NWA.N: Quote, Profile, Research) unveiled a merger proposal to shareholders.

The 6,000 Delta pilots have signed on to the plan, but their 5,000 counterparts at Northwest are resisting on grounds it hurts them economically and does not protect their seniority, which is crucial for a pilot's daily work arrangement, pay, and career advancement.

"The risk to Northwest Airlines and to the Northwest pilot group from letting this merger proceed, as it is now structured, is simply too great," said Dave Stevens, the chairman of the Northwest unit of the Air Line Pilots Association (ALPA).

Stevens said in a letter to members that Delta chief executive Richard Anderson on Monday rejected the union's suggestion the airline delay the merger announcement to try one more time to win support of the Northwest pilots.

Northwest pilots have concluded Delta management and its pilots have arranged to "disadvantage the Northwest pilots economically" regarding seniority.