Probably because the structure of that 3 year old files will not work anymore (due to core changes happened during development/improvements.)
How to get latest csv examples;
1. Visit demo site , click admin > airports > export csv (repeat for fleet, aircraft, airlines as per your needs)
2. Install phpvms v7 (either for a local test or for an online test), add at least one airport, subfleet, aircraft, then export to csv
Both options will generate examples (with some data) using the latest csv format v7 uses for import/export.