Right on. Always wondered, can you take a helmet as a carryon on the plane?
Yes, I've done it many times. Put it in a bag or helmet sock like what comes with new helmets. The flight attendants will ask "who has the bowling ball?" if they need to move it around when packing bags in the overhead. In most cases, it won't fit under the seat in front of you and they won't let you carry it in your lap during flight.
I have also just shipped a box of my gear to the dealership or the seller of a used bike, fly in street clothes, change into gear when I pick up the bike and strap a dry bag onto the bike if it has no panniers or top box for the ride home. A couple of those went like this: Wife drops me at the airport, fly to destination, ride train & bus close to seller location, pay and inspect bike, change into gear, ride to motel and sleep, on the road at 0400 and ride home that day. I rarely get lucky with bike deals I want close to home for some reason. It's like when you move and the nearest Chinese restaurant to you sucks, so you have to drive across town. I just have that kind of luck.
