If the Trump administration makes good on its promise to pack all potentially explosive laptops together in a blast-multiplying steel case in the plane's hold, it will be good news for would-be bombers — and bad news for your data security.
In addition to the physical risks to your laptop — theft, crushing, accidental swaps with other travelers' devices
— there are also infosec risks (for example, someone stealing your data, installing malware on your hard-drive or poisoning your USB controllers with undetectable BadUSB malware), and then there's the annual $1.1B price ticket (caveat: this number appears to have produced by the airlines through the highly suspect "rectal production" method) for lost productivity, delays, and additional screening.
Dan Gillmor proposes some operational security measures: encrypt your hard-drive, phone and tablet; use a minimal OS and data setup and access your working files over a VPN when you get to your destination; think about putting your data and OS on a bootable thumb-drive; and consider a Chromebook (if you're not worried about Google as your adversary).
Dan misses a couple tricks: first, you could use a flush-sitting USB drive as your bootable disk rather than a sticky-outie one that's easy to knock out. Second, you could remove your hard-drive prior to takeoff and fly with it in your carry-on to prevent data-theft and give you a bootable option when you land, even if your laptop is smashed or stolen (just buy another machine and swap in the drive). This works very well with most modern GNU/Linuxes, which are graceful about handling being booted into a new hardware environment (I've done this while touring, after dumping a cup of coffee in my machine and then swapping over to a different model I was able to buy in a computer store).
For the very paranoid: remove your USB ports (or fill them with superglue). Put tamper-evident tape over the screws on your laptop after you remove your laptop (or, if you've got 15 minutes, paint over them with glitter nailpolish and take photos of the glitter patterns after it hardens, then compare again before you put your drive back into your machine).
What to Do If the Laptop Ban Goes Global [Dan Gillmor/Backchannel]