good question. i have no idea haha

Yes. Especially if they are lined with thermal lining or interlining.

In business suits and similar clothing there is the cloth that you can see on the outside of the suit and a lining inside the suit, but, in good quality suits there is also an interlining layer of cloth which may be rough textured but stiff to give the suit its shape and fit.

Fusible felt is usually thinner than most interlining materials. When you iron the outside fabric on the fusible felt it literally fuses together. Do NOT iron the fusible felt directly, it will melt. Interlining is usually loose between stitching whereas if you iron both the top and bottom outer linings with the fusible felt in the inside both outer linings will become attached.

Side note: I am no expert I may be mistaken with the information I've provided. Mostly, I answered the question on intuition. I myself just heard of fusible felt yesterday. :D

Baggage Interlining is a voluntary commercial agreement between individual airlines to handle passengers traveling on itineraries that require multiple airlines. Interlining agreements differ from code sharing agreements in that code sharing agreements usually refers to numbering a flight with the airline's code (abbreviation) even though the flight is operated by another airline. However, codeshare relationships can affect whether an interline ticket can be issued. Both the codeshare marketing carrier and codeshare operating carrier must have interline agreements with all other carriers in the itinerary to allow a single ticket to be issued. Interline agreements are directional.