DH, LO, and I are flying to FL for a wedding in November. We've started looking into traveling with a 3-month old and are a little worried about all the large baby items we'll need to bring. We have a convertible car seat and weren't planning to use an infant car seat, but it seems like an infant car seat would be much more convenient while traveling.

I'm wondering, will we need to go the infant car seat route? I can ask to borrow from a friend I suppose. I'm also thinking we may be able to get away with leaving the playpen at home if we bring our City Select stroller because we have the bassinet attachment. Thoughts?
Re: Traveling / Flying with an infant
If you're not buying LO a plane ticket, make sure you're comfortable with checking or gate checking the car seat. Some people treat checked car seats as if they've been in a wreck and don't trust them. I've checked ours several times and just accept the risk. It depends on your comfort level.
Also, as already mentioned, checking a car seat (gate or otherwise) gives it an unknown history. Can you have a family member at your destination but a $40 one from Walmart and pick you up with it?
Baby Boy due October 2017
As far as I can tell, our options when traveling with small kids are: 1) rent a car seat at your destination or 2) bring one with you. I choose #2. That leaves either buying an expensive extra plane ticket or checking the seat. Given the choice, I choose to check the car seat. I was somewhat intrigued by the idea of buying a cheap car seat just for travel, but haven't done it. Technically DD's car seat has an "unknown reputation" from the baggage check, but logically it doesn't bother me that a safety device designed to withstand a high-speed collision may have gotten bumped around by a few baggage handlers.
If nothing else, I would recommend absolutely NOT checking the car seat.
I've seen too many car seats damaged this way
https://www.faa.gov/passengers/fly_children/
The FB group Car Seats for the Littles would have an awesome answer for you. Basically they say that the corrugated cardboard protects the seat.
Baby Boy due October 2017