Requirement, maintenance needs/costs, model, range, accomodation, comms, etc
Passenger needs, media, sleep accomodation, style, cargo limitation, comfort, galley, lav, etc
Personal, Business, Part 91-Part 135, Corporate, Owner, Fractional, etc
Aircraft economy, single, multi, piston, turboprop, VLJ, domestic, international, altitude, etc
Ground to ground service requirment, crew, certifications, etc
Annual maintenance, maintenance reccommendation, investment costs, etc.
Budget, purchase options, financing, base of ops, funding etc.