a 400 f2.8 and FX body minimum. Another body and couple of lenses if they fit would be good too. Major long haul aircraft 747/380/787Which lens(es), which airline(s)? There is quite wide variation in carry-on allowances from one airline to another. I wrote a blog post last year where I tabulated the maximum dimensions and weights of carry-on bags for about 60 major airlines:
http://lensesforhire.blogspot.co.uk/2016/09/flying-with-your-photographic-equipment.html
As Stewart said, be aware of the airline's specific size and weight limits. If necessary, be prepared to stick some bits in a pocket or 2 to get the bag under any weight limit.