Always a good idea to have the airlines firearms regs printed out so you can educate the counter personnel on what their company's policy is on traveling with firearms.
Ticket counter folks are notoriously ignorant and TSA is as bad or worse! Last time I had to open a bolt action rifle for the TSA agent so he could verify it was unloaded.

I am continually astounded at how quickly people make up their minds on little evidence or none at all.
Jack O'Connor