That said, there are special procedures for engine-inoperative ferrying (no passengers or cargo) a 3- or 4-engine transport aircraft - carefully spelled out in the airplane flight manual. These generally include special flight planning, special inspection of the good engines, and special crew training. The airplane is made as light as possible. Properly done, there is no undue risk.
And then there is the case of the publicity flight made by Aero Commander about 60 years ago; One propeller was removed from its engine and stowed in the cabin, the airplane took off from the Oklahoma factory, and flew to an airshow in Pennsylvania (or maybe New Jersey?) on the other engine. Again, it was all carefully planned out, but not intended to represent a recommended procedure.