The company implemented an expensive modification program (the Lockheed Electra Achievement Program or LEAP) in which the engine mounts and the wing structures supporting the mounts were strengthened, and some of the wing skins were replaced with thicker material. All Electras were modified at Lockheed's expense at the factory, the modifications taking 20 days for each aircraft. The changes were incorporated in later aircraft as they were built. However, the damage had been done, and the public lost confidence in the type. This and the smaller jets that were being introduced eventually relegated Electras to the smallest airlines. Production ended in 1961 after 170 had been built. Losses to Lockheed have been estimated as high as $57 million, not counting an additional $55 million in lawsuits. Electras continued to carry passengers into the 1980s, but most now in use are freighters.