connection fee - you get both types on your licence when you do the course for either, but you are not qualified to fly the other. To do that, you need to do a differences course and a sim check. Thereafter, you do alternative Base Checks (as they used to be called) or LPC/OPC's, this time round you'd do 757, in 6 months' time your sim check would be 767, and a year from now 757 again.