We actually do support importing a GPX file from a USB flashdrive. However, currently we do not support exporting a GPX file from the iPad or Android. This is on our wishlist and I'll be reiterating this next week in our development planning meeting. Potentially, an email or save to option would suffice.
We also have it on our wishlist to make the Flight Plan, Settings, Aircraft/Pilot profiles, etc part of a cloud based account feature. Basically push your Flight Plan, or Settings to your account, then pull it down to another device or as part of an update package. Stay tuned and thanks for the feedback.
Additionally, if you are using a combination of the 720, 740, iOS, Android and have a WiFi ADS-B device or other WiFi network device, you can use the Share with Local Devices under the More Options of the Flight Plan page. As mentioned in above post, this does not support the 700.