The sky over Lawrence will be used Thursday to pay tribute to the victims of the 9/11 terrorist attacks and to salute the military.

At 5:30 p.m. acrobatic sport planes will use smoke to write “9-11-01” in the sky.

“It’s in recognition of our fighting soldiers in harm’s way to prevent another terrorist attack,” said Al Stuber, a Lawrence pilot who will be flying one of two to four planes in the event.

The planes will be a mile high over the city when they write the message, Stuber said. The planes and their pilots are members of the Red Hawk Squadron, which has performed skywriting over Kansas University’s Memorial Stadium.

Last weekend at a 9/11 memorial event in Kansas City, Mo., the squadron also wrote the date in the sky.

“We got a good response from that and thought we’d do it here,” Stuber said. “This is a spur-of-the-moment thing.”

This is the first time the planes will have tried the event in Lawrence, Stuber said. Weather conditions will determine whether the skywriting takes place, he said.

The Red Hawk pilots are all former military pilots from the Lawrence and Kansas City area. Stuber was a Navy pilot.

Stuber’s own son, Pat Stuber, a member of the Tennessee Army National Guard, is preparing to go to Afghanistan, which will be his fourth combat tour.