You can try one of these 3 ways:
1. Zoom out until your board is tiny, then use the route tool and click anywhere on your PCB, this should grab the air wire. You can then zoom in and route it.
2. You can also run the provided "length.ulp" script (File > Run ULP...). After running the script, it'll tell you a list of all the nets. In the "Unrouted" column, you'll find the net that's not routed, double-click to reveal the air wire.
3. Another way is to disable the top and bottom layers to make the air wires more visible.
Hope these help!
Answered 1 year ago.