I have a hand held Garmin GPS which I have used on board commercial aircraft(with crew permission).It is a GPS V Model which I bought on ebay a few years ago.It's not always easy to acquire enough satellites to get a decent response but it does work.It has a map function and you can expand this with add ons via your PC
You can enter airway waypoints if you know their coordinates as well as your destination.Altitude and speed are shown too.
I'm not up to date with current models but I'm betting they are even better than the one I have.
I'm sure many PPLs on here will have up to date information.Good hunting.