I just had to share this tip.
My husband owns a leather jacket with a nice zip-out liner, but the leather jacket itself weighs a ton and would take up half a suitcase on its own. He also owns a good water-resistant windbreaker type jacket, but it has no liner so is not suitable for cold weather.
For our recent trip to France and the UK (including Scotland, where it was chilly and rainy most of the time), I customized the windbreaker to accommodate the liner from the leather jacket. I sewed jumbo snaps to the shoulders and bottom front edges of the liner (6 snaps in all). I sewed the mates to the snaps into the corresponding spots at the shoulders and bottom front edges of the windbreaker jacket.
Voila! A packable, lightweight, casual jacket with a removable, warm liner! (For dressier occasions he also brought a wool sportcoat.) We spent a lot of time outdoors on our trip and we were both extremely pleased with the way this wardrobe choice worked out.