In October 1915, Serbia was invaded by a combined Austro-Hungarian, Bulgarian and German force. The Serbian Army was overwhelmed within weeks and forced to retreat across Albania to the Greek island of Corfu. The small Serbian Air Force withdrew from its headquarters in Banjica to Kruševac via Mladenovac, Smederevska Palanka and Jagodina. In Kruševac, Tomić and lieutenant Živojin Stanković were tasked with destroying four obsolete planes to keep them from falling into enemy hands. Upon completing the task, Tomić and Stanković manned two small biplanes and headed for Peć. Tomić successfully reached Kosovo, but Stanković did not. His plane crashed near the town of Kuršumlija, leaving him seriously injured. Tomić continued south, successfully transporting the Serbian Government's gold reserves out of Niš and ensuring they did not fall into the hands of the Central Powers. He also flew important mail in and out of Serbia, and evacuated the country's hard currency reserves. In Kosovo, Tomić contracted typhus. On 19 November, he and aerial mechanic Miloje Milekić landed in Prizren. They spent the next two days wandering the countryside and walking through knee-deep snow. During the day, the air temperature reached . The two stayed near their plane, waiting for orders from the Serbian High Command. On 21 November, Tomić and Milekić received orders to destroy their plane and go to Albania on foot. They decided against destroying the Blériot XI and took off the following morning, headed for Durrës. The Blériot XI was designed to fly for a maximum of four hours, but Tomić managed to keep it flying for the duration of the four-and-a-half hour flight to Durrës and landed safely on a field near the town. Locals soon discovered the plane and escorted Tomić and Milekić to Serbian envoy Panta Gavrilović. Tomić recovered from his ordeal and later evacuated General Petar Bojović from Scutari to Lezhë. Heavy winds over the town caused Tomić's plane to crash on 23 January 1916. He escaped unharmed.
