Battle Bags were brands of crisps available in two varieties: Fighter Planes (salt and vinegar) and Tanks (cheese and onion). I mainly remember the advert which went something like:
"Squadron Leader to Tank Commander - looks rough. Over."
"'bout time we gave them a taste of our new battle bags"
"Roger I'll knock 'em out with our fighter jets"
"and I'll treat 'em to our tanks. Battle Bags Away!"