A passenger asks a question while you are greeting a long line at the door. How would you help without slowing boarding too much?

If a passenger asked a question while I was greeting a long line at the door, I would decide quickly whether it is a five-second answer or a longer conversation. If it was simple, I would answer it right there. If it needed more time, I would say, "Welcome aboard. Please head to your seat, and I will come right back to help once the line clears."

That approach keeps the doorway from turning into a bottleneck while still making the passenger feel seen. If another crew member nearby could answer faster, I would hand it off immediately instead of making the passenger wait unnecessarily.