When are Sue and Frank arriving?

W Harry, I just spoke with Sue. Her and Frank’s flight arrangements are set; they’re landing at South Airport at 5:30 on Tuesday.
M That’s my busiest day. We have a big deadline on Wednesday. I don’t think I’ll be leaving the office until 7 or 7:30, so I won’t be able to pick them up.
W Well, they’ve visited us here so many times I don’t think they’ll have any trouble taking the train out here. I’ll call her back and let her know.
M Or they could take a taxi. From the airport to here won’t cost more than $25, and it’s more convenient than the train.