Captain Carranza's return flight to Mexico City was originally scheduled for Monday July 9th, 1928 but was postponed twice because of poor weather. On Thursday, July 12th, preparations for the flight to Mexico City had attracted a crowd earlier in the day when mechanics of the Wright Company conducted a thorough pre-flight inspection of the "Mexico-Excelsior". At Captain Carranza's request, the airplane's fuel load was reduced from 430 gallons to 390 based on Captain Carranza's estimate for the 27-hour flight to Mexico City. Concerned that his heavily loaded airplane would pose a danger to the assembled crowd at Roosevelt Field in Long Island, Captain Carranza announced late in the afternoon the indefinite postponement of his flight in order to get the spectators to leave.

On July 12th, flying conditions over most of his route were described as ideal, except for weather in New York State. It appears Captain Carranza planned to hurry south to escape the northern storms and pick up good weather for the remainder of the trip. Eager to return to his bride of four months, he slipped away from the Garden City Hotel, where he dined Thursday night, and without telling anyone of his intentions to take off. At 7:05 pm, in secrecy, to avoid dangerous crowds while attempting to get airborne with a fuel-laden aircraft, and in between thunderstorms, Captain Emilio Carranza took off on the 2,400 mile non-stop flight to Mexico City. His B-1 Ryan Brougham Monoplane took off without difficulty after a 3,000 ft. run. Captain Carranza circled the airfield twice before heading south. He planned to circle Washington DC and then set a direct compass course toward Mexico City. He was expected to arrive at midnight on July 13th, 1928. The Associated Press wired news of Captain Carranza's departure to Mexico City, where word spread quickly. The people of Mexico eagerly awaited the return of their famous aviator. Mexican government officials, US Ambassador Morrow, and the entire staff of the United States Embassy in Mexico City planned to be at the Balbuena airfield to greet Captain Carranza upon his arrival.

At about 8:00 pm, the roar of an airplane was heard near Chatsworth NJ about 85 miles southwest of Roosevelt Field. Immediately afterwards, residents reported severe rainfall with lightning and thunder. This was to be the last contact with the "Mexico-Excelsior".

The following morning, along Captain Carranza's planned route over Galveston TX, vigils were set up in towns along the Gulf Coast to sight the Mexican aviator. US Army aviators stationed at Fort Crocket were also on the lookout. But there were to be no sightings of the "Mexico-Excelsior".