Complex sentence: The airframe is a similar but longer than the 737-700-based C-40 Clipper, which has has a 737-800-based fuselage with 737-900-based wings.
Split into simpler sentences: The airframe is a similar but longer than the 737-700-based C-40 Clipper. It has the 737-800-based fuselage with 737-900-based wings.