I traveled with a 5 week old last April and had no problems, I kept her in the sling most of the time or on my lap. That being said we had to go when we went, since it was likely, and did end up being, her only chance to meet her Great Grandfather. It wasn't a big deal to travel with her, I did have my parents traveling with me and they helped with DS as well which made things a lot easier. If I had had a c-section with DD it might have been a bit harder, though I probably would have gotten a wheelchair at that point in time. I was healed enough that I didn't have a problem with traveling and would have been able to do it as early as 2 to 3 weeks post birth (which is allowed by all the airlines I checked, most require a doctors note for under 7 day old babies only), but I was thankful to have a bit more time to recover.
A 5/6 week old on an airplane is easy, just nurse them as needed and let them cuddle and sleep, it is the older child that takes a lot more effort

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