I usually use an old North Face Snow Leopard 2 when travelling/backpacking. It was sold to me as an ice climbers pack thus it has the necesary 50million straps all over it. Also a very robust and heavy pack at 3.5kg or thereabouts from memory. Ive been on many plane trips throughout the world and no hassles with straps yet. All I do before boarding is tuck the ends of straps as much as possible; pull the harness straps as tight as possible to tuck the harness into the main body and lastly do the same with the waist belt. If I have anything on the outside of the pack its strapped by three straps to the side (tent and/or mat).
As for your whistle, strobe and other small items on the outside of your pack, I would locate them inside the pack for the plane journey. The rope should be fine as long as its strapped down by minimum 3 straps and not messy.
If I was travelling with a light weight non-framed pack such as what Golite make, I would buy a specially designed tough bag that can be put over your pack and has handles for the handlers to grab.
How I view it is in the eyes of a 'stupid' baggage handler (yes I know all baggage handlers are not stupid
), how do i make my pack easy for them to grab and how do I make my pack so they cannot damage it.
Hope this helps.