I use this bag with a&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/DSLR-Camera-Insert-Compact/dp/B00348J5Q0/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">DSLR Camera Insert - Compact</a>.  The insert allows me to carry a Sony A55 w/ 18-250mm lens, 30mm prime lens, spare batteries, filters and mini tripod.  All this takes up less than half the volume inside the main compartment of the Flight Bag. There's plenty of spare room for an additional iPad, 13" notebook, and other electronic accessories.  The Flight Bag is light weight but durable.  I have not had a chance to try and store this underneath an airplane seat yet, but by comparing this to another bag that I have used for that purpose, it should fit just fine.  To give you the maximum amount of interior space, there is not a lot of padding inside.  You'll need to provide your own if you plan to carry expensive electronics.  I'm happy with my purchase and expect this to last several years.