Configure an AirPort base station WITHOUT an ethernet cable?

Possibly, if you have a spare AirPort Express that can be set up to wirelessly join the hotspot network and then provide an Ethernet signal via an Ethernet cable to the second Express, which will then be configured to provide a wireless network for all of your devices.

Either the A1264 or A1392 version of the Express has this type of capability. Netgear also appears to have WiFi extenders with this type of capability as well, but I have not tested any of these devices.

In this type of setup, the first AirPort Express acts like a wireless "modem" to feed a wired Ethernet signal to the second Express.

The bottom line........if you want an AirPort to provide a network with Internet access on a third party network, there must be an Ethernet cable connecting the "modem" to the AirPort.

Please check my original response above again to see that I said that if you had a spare AirPort Express, then one Express could be set up to "join" the Verizon JetPack WiFi network using a wireless connection.......then......the second AirPort Express would be connected to the first Express using an Ethernet cable to provide an Internet connection for your devices.

This is the same type of setup that I use when I am traveling and the hotel has only a wireless connection. The first Express is set up to "join" the hotel WiFi network and a second Express is then set up to create my own private wireless network in the hotel room.

I can connect as many devices as I want to my "private" network in the hotel room and not have to share the same wireless network with other hotel guests.

If you decide to add a second AirPort Express, post back at that time and we will walk you through the setup.

The utility app doesn’t give me the option to join a network wirelessly (that’s my problem).

Yes it does, assuming that 1) the Express is not defective and 2) you have reset the Express back to its original default settings...... before.....you try to use AirPort Utility to set up the Express to "join a wireless network".

The setup for the Express will look like the example below when you run AirPort Utility and choose the Express as a new AirPort Base Station. Below, you see an Express that will be set up to join a wireless network that is named "2WIRE902".

But, there is no value in trying to set up your Express to "join" the network until you have a second Express.

You do have two AirPort Express devices, correct?

You will first need to set up the AirPort Express that will "join" the available wireless network at your location and act as a "modem"......then.....set up the other AirPort Express that will be configured to "create a wireless network".

Whenever you are setting up an AirPort to perform a different task, you must reset the device back to factory default settings. If you don't, AirPort Utility will not recognize the device at all.

For now, work only with the AirPort Express that will act as the "modem". Leave the other Express powered off until the first Express is up and running.

When the first Express is set up, use an Ethernet cable from the LAN <--> port on the first Express to connect to the WAN "O" port on the second AirPort Express. This Ethernet connection must be maintained at all times.