The exercise involving three district level officers was described by officials as being in line with the Election Commission's directive to ensure free and fair elections in Karnataka.
"It was a random search by a team led by (election) nodal officer Karpale. We searched the planes in which Rahul Gandhi and Amit Shah had arrived. It was not intentional," Deputy Commissioner of Dharwad district S B Bommanahalli told PTI.
Mr Shah and Mr Gandhi arrived by separate planes at Hubballi airport from New Delhi.
Soon after their arrival, a team led by election nodal officer Karpale and Hire Gowda and Yogananda searched the planes to check for possible poll code violations.
Mr Gandhi, on the fifth leg of Karnataka tour, left for Shivamogga and addressed public meetings there and in Davangere.
Mr Shah, also on the fifth lap of Karnataka tour, addressed an Other Backward Classes convention at Kaginele in Haveri district and had an interaction with the seers of Veerashaiva community at Shivayogi Mandir in Badami taluk of Bagalkote district.