The Travel Pack 4 is the fourth generation of Aer's one-bag travel backpack, a structured carry-on pack that opens flat like a suitcase for clothes and packing cubes, then keeps a laptop and daily tech in separate, organised compartments. The 35L version is the full-size option, aimed at three to five days in one bag, while the 28L version trims the same idea down for shorter trips and smaller frames. It made the cut because it stays useful after the airport. The silhouette is plain, mostly black and office appropriate, the main compartment is built around cubes rather than loose packing, and a padded, suspended laptop compartment for up to a 16-inch machine sits apart from clothing. Front organisation handles chargers and cables, and load lifters, a sternum strap and luggage pass-through details show the pack was designed for actual transit days, not just capacity figures. Aer lists the Travel Pack 4 35L at $259 USD on its own store, with X-Pac at $289 USD and Ultra at $309 USD, and the 28L from $239 USD. The standard shell is 1680D Cordura ballistic nylon, bluesign approved in Aer's specification, with YKK zippers, dimensions around 21.5 by 13.5 by 9 in and a weight near 3.9 lb depending on fabric. Verdict: heavy for its litres and priced at the top of its class, but still the benchmark one-bag pack for organised travellers
