| Cause | Different political and economic conditions • Internal migrations due to environmental changes |
| Major migration | Limited global human movement |
| Alternate history | Stable, Immobile Societies |
| Short-term travel | More common with developed air travel |
| Historians' debate | Potential for more homogeneous societies • Less multiculturalism • Higher social cohesion |
| Effect on migration | Few major demographic shifts |
| Impactful technology | Air travel |
| Long-term population shifts | Not significantly impacted by air travel |
