If you are visiting any website, make sure you differeniate the real sites from the fake sites as so many people have been defrauded online by scammers who clone popular sites.
Below are the original websites of Nigeria's major domestic airlines:
Arik Air: http://arikair.com
Aero Contractors: http://flyaero.com
Air Peace: https://www.flyairpeace.com
Dana Air: http://www.flydanaair.com
Medview Airlines: http://medviewairline.com
Overland Airways: https://www.overlandairways.com