title kind of sums it up. how do y'all pack your panniers for the flight so you don't get stuck with charges for having extra bags?

Get a really cheap "army-surplus" type of duffel bag to stuff your panniers in for the flight. Some cheap nylon ones are pretty light and will probably survive the trip if you put lots of tape around the bag. Throw the bag away when you get there. Worry about the return trip when you get to that bridge.

I put some stuff into the box with the bicycle, but the rest (including the panniers) I place all together into a heavy canvas laundry bag .... the kind you can pick up for $12 from Walmart in their laundry section. Don't scrimp and buy the $8 one with no shoulder strap ... splurge and get the one with the shoulder strap, it makes a world of difference when you've got to haul the bag from point A to point B in the airport (or bus station or train station) and you don't have the correct currency to pay for those little carts.

The great thing about these bags is that they are light enough to carry with you, and they make great pads for under your mattress, or folded they can become a second pillow. I think I've even used mine draped across my feet on one occasion when it got quite chilly that night.

Or if you discover you brought too much stuff and have to store some at a friend's place for a couple months while you tour, you can put all your extra stuff into that canvas laundry bag so that it is in one convenient location. That way when you get back to your friend's place at the end of the tour, you can just pick up the one bag.

I've been using the canvas laundry bag method since 2003, and it works very well.

I have used cardboard boxes for things that I picked up on trips or items that were only traveling one way. they are as cheap and easy as you can get. I really like Machkas laundry bag idea. I think the shoulder strap could make things easier to get around. Cardboard works well but it can be a pain to transport without a luggage cart or if you have other bags.

Those canvas laundry bags are surprisingly durable too. I used one for several trips, including to Australia and back, before I retired it to be used as ... a laundry bag ... and bought one with a shoulder strap for travelling purposes.

And the two worst times I had with carting the laundry bag without the shoulder strap around were here in Canada. I had just spent about 3 weeks in Europe and had pockets full of Euros and British coins. I landed at the airport in Toronto to transfer to my flight home ... and discovered I needed a loonie for the carts .... and I didn't have a single loonie on me!! Then just last year, I was returning to Canada from California. I had a fairly lengthy wait at the Vancouver bus depot, and discovered when I got there that they do not have carts at all anymore because people keep stealing them. So there I was trying to haul a cardboard box containing my bicycle, and my laundry bag, all over the terminal trying to find my bus. I rushed out and got a bag with a strap after that.

BTW - the laundry bag method makes for a very recognizable piece of luggage coming around the carrousel! Everyone else in the place will have pristine-looking identical black suitcases, but you will have a slightly dirty, off-white laundry bag!!