Hmmmm... One company that makes flares is Orion. They can be bought online from WestMarine stores but I don't know to what degree are they water/pressure proof. Of course they have to be water resistant and Coast Guard approved but that also means that any boat bigger than a kayak should have a full range of signaling devices. <br><br>Now movies such as teh Abbys and Thunderbolt (with 007) feature underwater flares that are pressure and water proof but my reaserch returned only flares that are good down to 12-15 feet. This is an article about it as well as last time poeple heard from them:<br><br>http://www.boatingoz.com.au/news000714.htm<br><br>Ignoring all that and assuming that you find one I think that there may be a possible safety issue while trying to transport flares on board of the plane. After all 12 gauge flares are or can be considered a weapon and regular launching flares still are a projectile. But that's my 2 cents. Get an Aqua Strobe it will do the job. Plus the minute you start adding more and more stuff to take with you underwater more uncomfortable you become. It's not like you can take a backpack with you. Everything has to go into your BCU which really is not the roomiest thing in the world.