Not sure exactly what you are asking..
The TC can do the same as the AE .. it can extend an apple wireless router.. no ethernet required.
But it cannot do what the express does in working as a bridge to a non-apple wireless router.. it will only work as a client.
To be useful, you need internet connected by WAN port by ethernet. But all the LAN clients can use wireless is no problem. Or you use it with another apple router.