A skywriter was hired to canvas southeast Michigan, but was not targeting Michigan State, said David Ablauf, a spokesman for the Michigan athletics department, which paid for the writing job.
"Go Blue" is a Michigan slogan. The school's colors are maize and blue.
Suzanne Asbury-Oliver, co-owner of Oregon Aero SkyDancer, said the company was asked to write over East Lansing. The University of Michigan had hired the company to skywrite on three previous occasions. Their work doesn't come cheap.
"It's a multi-thousand-dollar job," Asbury-Oliver told MLive.com. "First, it's $2 per mile for how far we have to take the plane, then the lightweight oil we use (to skywrite) is expensive, and we use about a gallon and a quart each letter. Then for these kinds of jobs you have to throw in hotels and all that."
Michigan State Alumni Association Executive Director Scott Westerman used the "Go Blue" message and occasion to encourage Spartan fans to donate money to fight ovarian cancer. It had raised more than $9,000 as of late Tuesday.
His wife, Colleen, is a two-time ovarian cancer survivor who received care at the University of Michigan Comprehensive Cancer Center.
Scott Westerman also encouraged University of Michigan alumni to match the Spartan fundraising effort.
Ablauf said the skywriter made other stops Saturday, including one above Michigan Stadium where the Wolverines were playing Akron.