Carrying small pliers and screwdrivers at all times is helpful and comforting. So, when I travel without checked baggage, I feel strange leaving small multitools behind. Being without tools is weird. So, I decided to buy a used Leatherman Squirt on eBay (possibly a TSA auction of a previously confiscated tool), and modify it to meet/exceed the government restrictions on carry-on tools.
Step 1: Acquire a High Quality, Low Cost Multitool to Modify
Since there's every likelihood that at some point your multitool will be confiscated, regardless of it's compliance with regulations, don't spend a lot of money on your tool. I like the Leatherman Squirt series. Brand new, they're around $30. Used ones go for around $10-$15 on eBay. I've bought three used ones over the years and they've all performed admirably.
Step 2: Remove Rivits and Disassemble (optional, Mostly Unnecessary, Yet Fun Step)
Mill or grind off the rivets with a Dremel or angle grinder to remove or swap out the offending parts. Originally, I'd planned to exchange other compliant parts from a second donor tool, but none were unique enough to warrant it. It was fun to open, and does make grinding the file, awl, and blade easier, but you really can skip this step if you like.
Step 3: Dull, Round, and Shorten Blades
You can use pliers to snap the file down to size, or simply grind it down to size and then round it. The same goes for the main knife blade. The awl is a bit pointy and threatening on this one, so you may want to defang it as well.
Step 4: Laser Etch "TSA Compliant" Into the Scale
Since you've gone to all this trouble to make your multitool compliant with the TSA rules, why not advertise that a bit? If you have access to a laser cutter/engraver, you can etch it yourself, or bring it to an engraving shop and have it done for you. Use the attached file for a Leatherman Squirt, or scale accordingly for your tool.
I managed to travel through about six airports before this one was confiscated. Not too bad for a ~$12 investment and two hours of my time. It was really helpful to have the tool with me when traveling light. I plan to make a replacement before my next trip. If you make one for yourself, I'd love to hear of your adventures with it!