Air travelling with IK

I’m trying to figure out the logistics required to air travel with an inflatable kayak for a 2-3 days trip on a river. I’m intending to take my 8 years old son with me as well. Can anyone with experience can offer some tips? Or point to a good resource?

The kayak is a Gumotex Seawave - 4.5m tandem, 18kg, packed in 100L drybag (which I can probably carry on my back, and use for equipment while on the water). But how to carry all the gear when I’m getting to the launch site? Rolling duffel bag which I can pack inside the kayak? Or is it easier to rent a car?

I don’t have a specific destination yet (somewhere in Europe), just trying to plan everything out and get the required equipment before the spring