Looking at the picture of the three Boeings, got me wondering
How many airlines still show registrations on the underside of the wing, and how many on the top as per JAL?
45.045 Number and location of sets of markings — fixed-wing aircraft
(1) On a fixed-wing aircraft, 3 sets of the aircraft’s markings must be displayed, as follows:
(a) 1 set either on the under surface of the port wing or across the under surface of both wings, in each case as set out in subregulation (2);
(b) the 2 other sets on:
(i) the fuselage, as set out in subregulation (3); or
(ii) engine nacelles or similar fixed obstructions on the fuselage, as set out in subregulation (5); or
(iii) the vertical tail, as set out in subregulation (6).
(2) A marking on the wing of an aircraft:
(a) must have its top towards the leading edge of the wing; and
(b) must be as nearly as possible parallel to the leading edge, and half-way between the leading and the trailing edge, of the wing.
(3) If the markings are on the aircraft’s fuselage, there must be 1 set on each side of the fuselage:
(a) between the trailing edge of the wing and the leading edge of the tailplane; or
(b) if the aircraft is of canard configuration and has no tailplane — between the trailing edge of the foreplane and the leading edge of the wing.
(4) In subregulation (3):
tailplane includes the tail surfaces of an aeroplane that has a vee-tail.
(5) If there is an engine nacelle or similar fixed obstruction on the part of the fuselage mentioned in paragraph (3) (a) or (b), there may be a set of markings on each nacelle or obstruction.
(6) If the markings are on the aircraft’s vertical tail, there must be :
(a) if the aircraft has a single vertical tail — 1 set on each side of the tail; or
(b) if the aircraft has a multi-vertical tail — 1 set on the outer side of each of its outermost surfaces.