help!!!!!! traveling moms!

OK. So I'll be moving back to Cali in a month & a half traveling by plane with my (will be) 6 month old & 4yr old. I want to bring my pack n play along with stroller & carseat + my carry-on. Does anyone know if ill have to pay for the pack n play to fly? will they allow me to still have my carry ons for each ticket? I've flown with my daughter before but she was almost one the first time & we didn't bring her stroller just the carseat diaper bag & my luggage. They second time she was almost 3. we both just had our carry ons & her carseat & one checked bag. Ths time I feel like I have so much. Tips please!!!!!