You can take the word of someone who had a few bad experiences with headwinds, and resorts to ad hominem attacks when his word is countered, or you can check out the historical records of winds at several towns along your route at
http://www.wcc.nrcs.usda.gov/ftpref/...mate/windrose/
Note that most of the Wichita, Kansas "headwinds" come out of the south. East-west in Kansas occurs in the jet stream at 30,000 feet.