Adds second senator comment, more details in paragraphs 3-9

By David Shepardson

FARNBOROUGH, England, July 20 (Reuters) - A bill passed by the U.S. House of Representatives last week to make daylight saving time permanent will face a tough fight in the Senate to win approval, a lawmaker said Monday.

Senator John Kennedy, a Republican, said President Donald Trump called him recently to ask him to support the bill to end the twice-yearly practice of changing clocks that has been observed across most of the United States since the 1960s.

Kennedy said he agreed to support it but said there is significant opposition in the Senate. "It's going to be a dog fight," Kennedy told reporters on the sidelines of the Farnborough air show.

Senator Jeanne Shaheen, a New Hampshire Democrat who is part of a U.S. delegation at the show, expressed mixed feelings. "I feel it every time we change the clocks," Shaheen said, noting the change would result in "putting kids on the bus in the elementary school when it's still dark in the morning. I appreciate the safety concerns."

Last week, Senate Majority ‌Leader John Thune said it was unclear whether the daylight saving bill could garner the 60 votes needed for passage in the chamber.

If enacted, clocks would no longer return to standard time in November, although states could opt out of year-round daylight saving time if they do not ​currently observe it.

Supporters ​say changing clocks disrupts sleep, increases workplace injuries and contributes to more road accidents. They argue keeping ‌clocks ⁠an hour ahead year-round would provide more evening daylight and boost economic activity during the winter months.

Critics note the change would mean the sun rises an hour later on winter mornings, leaving more children traveling to school and commuters, construction workers, farmers and others heading to work before ​daylight. In some places ​the sun would ⁠not rise until nearly 9 a.m. or later at the height of winter.

The U.S. used year-round daylight saving time during World ​War Two and enacted it again in 1974 to reduce energy use. But it proved deeply unpopular and Congress repealed ​it later that year.