In coming days, keeping data and information secure in virtual reality is becoming a huge challenging issue with the advent of Quantum Computing. To deal such challenge, in the present work, based on Unmanned Aerial Vehicle (UAV) communication, blockchain is integrated with a postquantum cryptography (PQC) approach i.e., lattice-based cryptography for key agreement mechanism to make secure communication. The communicating UAVs generate and share keys among them through an insecure channel, hence to make such communication secure against multiple attackers Elliptic Curve Diffie Hellman (ECDH) encryption and lattice-based methods are used. ECDH in the blockchain is used to generate the lattice keys which are used in lattice-based methods such as Ring-LWE and N-th Truncated Polynomial Ring Units (NTRU) based quantum resistant encryption protocols, are used as key derivation functions. The suggested methodology ensures secure UAV communication and privacy of transmitted data is also concluded according to a thorough security analysis and protocol comparison results.