Iomega Harddrive that I am trying to connect to a MacBook Air

Tell us the model of the iOmega drive first.

Then, exactly what cable you bought and where on the drive it's connected to.

Does the drive have a status light? Does it light up when connected to the Mac?

What hub do you have exactly?

What port on the hub is the drive connected to?

Since it's not showing up, there's not much to do on the Mac at this point. You need to sort out any potential issue with the drive or the connection.

Even if the drive is corrupted or formatted in a way the Mac can't access, if the connection works and the drive works it should appear in Disk Utility at the very least.

Is it this one: https://www.usermanuals.au/iomega/minimax/manual

If so, what port on the drive is the USB cable connected to exactly?

Is the drive connected to power?

Data usually is part of your Mac's hard drive.

The drive should appear in Disk Utility under "External", like your other 1TB drive.

If it's not there, it means it has not been correctly mounted.

Several reasons for that, including the drive inside is dead, assuming of course it's connected to power.

If it's not connected to power, then it simply won't start up.

There's technically 4 USB ports in that picture. The one you want to use is the tunnel looking one next to the DC-In port. The other 3 regular looking USB ports are passthrough only.

If the light in front turns on, but the drive makes no noise, it's possible it's simply dead. Or the enclosure failed.

It may be possible to open the enclosure and extract the drive and use a different enclosure to test the drive.