On December 29, 2014, just in time for your 2015 world tour, the US department of Transportation promulgated the regulations that will, finally, put into effect the FAA Modernization and Reform Act of 2012. The regulations, and, thus, the act become effective 60 days after the regulations are published in the Federal Register, which should occur early next week.
So, what does this mean for us bassists? It is pretty vague. While the documentation seems to acknowledge that the 115 linear inch limit won’t work for bassists, the language isn’t strong enough to dictate that airlines will have to change their policies:
“Cases for (stringed) double basses are larger than the 115” size limit, and these instruments may also be sufficiently large to preclude them from being flown as carry-on baggage in a separately purchased seat. It therefore appears that nearly all large U.S. carriers would need to modify their current instrument transport policies to take into account the Act’s and rule’s requirements.”