When flying in other people's airplanes, I've used a setup that plugs into a cigarette lighter, the GPS puck was in the corner of the glare shield and the radio antenna was velcro'd near a window.
Don't forget about the licensing & operations requirements for the tracker. And stay within the guidelines to avoid being considered a major/minor alteration.
If there is no cigarette lighter option, you can get units which run on battery. Just don't try to use smart beaconing as it uses more battery power.
You have options from purpose-built trackers to hand held APRS-capable radios like the TH-72A.