I had a quick look at the Bluetooth options and confirmed my guess: Apple doesn't allow Bluetooth file sharing other than through their own Airdrop protocol. That means that file sharing through Bluetooth is only available between Apple devices, or between non-Apple devices, the two don't mix. I guess you'll have to find a place with a decent WiFi connection and spend a bit of time on this. Another option would be a USB drive with a Lightning/Micro-USB connector that works with both iDevices and Android (here's an example:
but there appear to be several options available). With that you could transfer to the drive, then transfer from drive to iPad. I don't have any experience with this and I'm always a bit wary of cheap solutions with things like this, but as you'll most likely only use it for this particular purpose, it might fit the bill.