In order for you to visit them, they'd have to come out of the terminal, past the TSA checkpoint, to see you where the ticket counters are, because TSA won't let you into the terminal if you don't have a boarding pass to fly somewhere. Then they'd have to go back through TSA and show their boarding passes to Nebraska in order to be let back into the terminal.
Unfortunately, you cannot..since you have to pass through security.but they sure can come out and go back in again.
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