Iowans in at least five counties will soon see low-flying biplanes, buzzing over rural highways — but it’s not a terrorist attack or a pilot in trouble. Ole Skaar, an agronomist at the Iowa D-O-T, says the yellow planes will be dropping seeds for native grasses and wildflowers as part of a roadside erosion control project. Skaar says it’s important to let the people know what they’re up to.He says many concerned people call their sheriff’s departments to report the planes which might appear to be suspicious or in danger. Flights should be starting later this week or early next week, lasting through the end of March. Skaar says motorists who encounter one of the yellow, twin-wing planes, called an Ag Cat, don’t need to take an alternate route.Skaar says this method of roadside erosion control has been used by the D-O-T for years because of its cost-saving benefits, ability to cover vast areas and success rate. He explains why it’s best for the grass seeds, flower seeds and fertilizer to be air-dropped at this time of year. The biplanes will be zipping along between 30 and 100 feet off the ground at speeds between 60 and 100-miles an hour. Areas slated for aerial plantings include: Bremer/Chickasaw/Floyd counties on U.S. Highway 218 from Plainfield to Charles City, Jones County on Iowa Highway 151 from Anamosa to Monticello and Monticello to Cascade, and Marion County on Iowa Highway 5 from one mile north of Pleasantville to Iowa Highway 92 and one mile east on Iowa92/Iowa 5.