Boeing and engine supplier CFM International solved the problem by placing the engine ahead of ( rather than below ) the wing . They also moved engine accessories to the sides ( rather than the bottom ) of the engine pod , giving the 737 a distinctive non-circular air intake . Boeing and engine supplier CFMI solved the problem by placing the engine ahead of ( rather than below ) the wing , and by moving engine accessories to the sides ( rather than the bottom ) of the engine pod , giving the 737 a distinctive non-circular air intake .