Questions with aviation in mind:
1) Anyone using BadElf (and the like) instead of built-in GPS ?
2) Advantages/disadvantages to add-on GPS units ?
3) How much memory is enough 32GB, 64GB or 128G ?
4) iPad Air future proof enough ?
1. I had a Cellular/Built-In iPad for a while but decided to go to a WiFi + Bad Elf Pro recently. I have the Bad Elf Pro hardwired to the avionics master, set in the startup to power-on automatically when the unit sees power, and no password on the Bluetooth. Whenever I get in the plane, it connects automatically to multiple units without issue.
Interesting, when I got the Bad Elf, I played with it. Put it up front and center on the dash -- and got 3m resolution. Placed the unit in the side pocket (Bonanza) and it still got 3m resolution. Put it UNDER the pilot seat and it got 4m resolution. WRAPED IT IN FOIL then put it in the glove compartment, and it got 4m resolution. Finally just attached it to the panel with the power cable hid/going back behind the panel.
2. Biggest advantage I can attest-to with something like a Bad Elf unit vs a 3G/LTE iPad is being able to provide GPS signals to MULTIPLE devices at once. I have overheated my iPad 2-3 times and still had my iPhone working fine and getting a Bad Elf signal. It's a minor thing, but it's nice to turn on the iPhone after an iPad shutdown, open the backup Foreflight copy, push one locate button, and see your position on a chart within seconds. Also, my 82 year old aunt flies with us from time to time. She has a Wifi iPad and is obsessed with knowing what town is out the window. I bought her a cached-map app called Co-Pilot. Download 1GB or so of maps, link it to the Bad Elf, and she always knows where she's at -- even without getting an Internet connection.
3. 32GB will get you by if you use it for nothing else. 64GB is really the minimum if you will also be using the iPad out of the plane... If you really intend on using it extensively (I download movies via the Tivo App for for my kids on long x-countries), the 128GB is only $100 over the 64.
4. I'd venture to guess you'd get a solid 2 years out of the Air... Maybe longer.