Originally Posted by
MSPeconomist
OP is going to a hotel for the night from the airport. The interview is the following day. It would be pointless to change at the airport so as to wear the interview suit to arrive at the hotel.
Yes, that became clear on re-reading the OP's post. My mistake.
Whether a professional looking backpack is acceptable depends on the OP's field and level. It's not a universal no-no IMO. Many interviewers would understand a non-business student bring a backpack to interview for an entry-level position. In other areas, such as computer science, most research, and academia, a backpack would not even be noticed.
If you're going through the trouble of taking a separate suit and are concerned about steaming out the wrinkles, then I read that as a signal you're concerned about making the bet first impression, as least visually. So things like proper grooming and polished shoes will matter as well. I would personally disagree that there is a professional looking backpack that goes with that. Invest in a briefcase or computer bag, they don't need to be that expensive. Otherwise the whole image is like going to a fine dining restaurant and hoping to order a hamburger. On the other hand, if you're interviewing for a tech startup, a suit is probably the last thing you'd want to wear. And keep the backpack!