Try looking at the providers of polytunnels. A google search will throw up the main manufacturers/distributors. I bought a small one recently for cultivating fruit etc. but noticed they come in all different sizes and it struck me there might be a use for one as a temporary hangar. You may have planning permission issues to deal with - they've become quite an emotive subject in some parts of the UK recently - but I think the presumption is they are a temporary structure.