I use a double bow SKB for one bow, some arrows, and some gear. Then I have a Badlands Terraglide clone that i put another bow, some arrows, and some gear in. I either wear my boots or put them in my carryon along w/ optics, releases, and raingear so I still should be good to go if 1 bag gets lost.
Good strategy^^^
I do something similar but use the Sitka Nomad [off season $280] and a big rolling duffle....The light bag is a huge advantage [the Nomad is 10.5#] which lets you take more gear and stay under the 50# airline limit. I pack my compound in the bottom of the nomad in a $20 soft case....works slick.
The airlines screwed us with a 50# limit...the light hard bottom rolling duffles are the way to go.
Your thread and question are timely, as I am facing the same dilemma...
And since I can't heli-arc weld myself a cool looking aluminum case, I'm goin' country, cheap, strong and light on my solution--- I usually like pretty, but in this case pretty does not matter.
I'm getting a cardboard box-bow from my local bow shop that will just fit my bow and I'm going to fiberglass the box and the lid inside and outside. I will also lay an extra layer or two in the corners so they won't crush. I am only packing one bow, but see no reason this won't work for two bow boxes.
My thought process is that surfboards are very strong and they are just made of fiberglass over rigid foam. Cardboard can absolutely be used to fiberglass over, I will put fabric tape or Gorilla tape over the hinge area to strengthen it and not 'glass that portion of the box. I will also glass in spacers of cut off 2''x4"s inside the box so the lid or bottom can't crush down on the bow. I will not worry about making the box lockable, I'll just tape it shut with nylon strapping tape. Am not worried about it popping open.
Once the box is made, I am going to stow it in the bottom of my rectangular gear duffle (as suggested by other posters to this thread), then throw a bunch of clothes on top and check the bag. I figure the bow box will weigh under 10 lbs once it's made, bow weighs about 5lbs, duffle only weighs a couple pounds- so that means I can put another 30+lbs of gear in the duffel on top of the bow box. Stabilizer and sight will go in my carry on. I think my rest can stay on the bow.
Anyhow, I spoke with a buddy who works with fiberglass all the time, he offered once key piece of advice: use a resin that contains wax because it will dry hard and slick, do NOT use laminating resin because resin with stay sticky for too long before it totally sets up. Once the resin is set up, he said to hit it with an orbital sander w/220 grit to knock the nibs down and then I'll be good to go.
Wish me luck!
JL