By Bernardo Vizcai** June 26 (Reuters) - Airbus Group and the Jeddah-based Islamic Development Bank (IDB) are seeding a sharia-compliant aircraft leasing fund to cater to growing demand for commercial financing from airlines in the Middle East, Asia and Africa. The fund, which will exclusively finance Airbus aircraft, has a target size of $5 billion and could help boost the European planemaker's edge against rival Boeing in the fast growing commercial airline market in the Gulf region. The European planemaker developed the fund together with Dubai-based Quantum Investment Bank and Palma Capital, and will seed it together with the IDB. Cayman-based International Airfinance Corporation will serve as fund manager.