Endurax Extra Large Camera DSLR/SLR Backpack for Outdoor Hiking Trekking with 15.6 Laptop Compartment

How comfortable are the straps with it fully packed during a long day of international travel?

it sait it comes with a rain cover ..but it is made with fabric or zippers to repeal the rain or water resistent with out the rain cover???

How wide is the flap on the bottom portion of the bag? Also, what is the interior depth? I am trying to see if this bag would be suitable for fishing.

Does this fit the size requirements to be a carry on? I don't want to risk losing my gear, so I need something that i can bring with me on plane!