July 13 (Reuters) - United Airlines Holdings Inc and its pilot union are back at the negotiating table for a new contract, after reaching a tentative agreement last month, CNBC reported on Wednesday.

The United branch of the Air Line Pilots Association (ALPA) said the current agreement "fell short" of some pilots' expectations, according to the report. (https://cnb.cx/3AJycsN)

United Airlines and ALPA did not immediately respond to a Reuters' request for comment.

The tentative deal approved last month was set to give pilots a more than 14% pay raise in the next 18 months when calculated from the beginning of the year.

The two-year agreement, previously approved by union leaders, was sent out to members for ratification and expected to settle by July 15.

United was the first major U.S. airline that reached an agreement with its pilots on new contract and was expected to act as a benchmark for contract negotiations at other carriers.

ALPA represents more than 62,000 pilots at 38 U.S. and Canadian airlines, making it the world's largest airline pilot union, according to its website.

Almost all the major airlines have been facing protests from pilots demanding higher pay and improvements in "fatiguing" schedules in their new contracts.

To attract and retain talent, three regional carriers owned by American Airlines this month announced hefty pay increases for pilots. Piedmont Airlines increased pay for its pilots by as much as 87%. (Reporting by Shivani Tanna in Bengaluru; Editing by Rashmi Aich)