CHICAGO, May 11 (Reuters) - United Airlines must offer its pilots higher pay than Delta Air Lines did to win a new contract, United's pilot union head Garth Thompson said.

In an interview, Thompson told Reuters the Chicago-based carrier has only been willing to match Delta's pay. United's pilot contract came up for renewal in 2019 and negotiations have been under way for five years.

Delta's landmark pilot contract offers $7 billion in higher pay and benefits, and it is putting pressure on rival carriers to hand out similar deals ahead of a busy summer travel season.

"We are in a positive pattern bargaining environment and we expect our contract to raise the bar from Delta's contract," Thompson said.

Airlines tend to have pattern bargaining. When one deal gets done, unions at other carriers use that as a benchmark to negotiate their contracts.

With pilots in short supply and air travel demand booming, United pilots feel they have leverage to win a better deal than Delta's did.

Thompson said United's pilots also want a contract that meets or exceeds the standards set by Delta's deal in improving work-life balance.

"Quality of work-life provisions have been the focal point for our proposals," he said. "There are still significant disagreements at the table on those work provisions."

In a statement, United said it is working with the pilots' union on the "industry-leading deal" that it has put on the table.

A person familiar with the contract negotiations told Reuters that United has proposed on average 18% pay increases in a new five-year contract for pilots. The company has also agreed with 79 quality-of-life improvements proposed by the union for the next contract, the person said. (Reporting by Rajesh Kumar Singh Editing by Chris Reese and Cynthia Osterman)