I want to transfer data from an original iPad (OS 5.1.1) to a new iPad Air using iTunes backup. All the advice I've read tells me to upgrade the OS, but that can't be done with the original iPad. Will it work anyway?

Transfer content from an iPhone, iPad, or iPod touch to a new device

Try backing them up and then on your new ipad copy and paste them if not use a site like dropbox

Do not worry my friend, it is very simple.

As Kappy correctly mentioned the article, you will need to create an iTunes or iCloud backup of your original iPad.

An iTunes backup is the easy and faster way as the data transfer rate is much faster due to USB speeds but there is always the risk of data corruption.

An iCloud backup is much safer in terms of data encryption and you have almost zero chances of data corruption. However because of the fact that you will be using the upload speed of your internet connection it will take considerably more time to perform and complete this backup type.

These being said, both of the backups contain your settings, mail account setup, camera roll pictures, in-app data (for most of the apps), etc. so it is the best way to save your files even without the will to restore it on a device.

Now after you have chosen a method to perform your backup you will need to restore it to the new device. Again, the method differs depending on the way you chose to do your backup.

If you have done the backup on iTunes, all you have to do is connect the new iPad, then go to files->devices->restore from backup.

If you have done the backup on iCloud you can only restore from that backup while you are within the Setup Assistant. This means that you iPad needs to be erased or restored and at the setup assistant you will need to choose "Restore from iCloud Backup".

Below are some links to assist you performing the following steps:

Should I use iTunes or iCloud to back up my iPhone, iPad, or iPod touch? - Apple Support

Back up and restore your iPhone, iPad, or iPod touch using iCloud or iTunes - Apple Support - Jump to the section "Restore from iCloud / iTunes

I hope I helped,

have a nice day.

The quickest and surest way to transfer everything is via iTunes on a computer. Make sure it is set to store the backup locally on the hard drive and make sure you set it to be encrypted with a password. When you Restore the backup on the new device you will be asked for the password but everything will get copied over.

I use an app called Retro.

It allows me to transfer between iDevices and also my computer,

all wirelessly of course. Check it out, you might like it.