If you've been sent an .ipa file from your developer, and want an easy way to install it on air, then you can use InstallOnAir.com to easily install this app on your device.
The Install On Air is online IPA installer tool. This robust platform allows developers to distribute their iOS and Android apps and install it over the air.
Easy Beta App Installs for iOS and Android. InstallOnAir keeps your devices and profiles up to date. Just upload your IPA or APK and InstallOnAir will do the rest.