Bike boxes for air travel - P-burgh

Hello forum readers! I was wondering if anyone could offer some advice and/or help me to solve a problem. My family of 4 will be riding the C&O and GAP trail next week from DC to Pittsburgh. We live in Oregon, so we’re flying with our bikes to DC to start our trip, then we will fly home from Pittsburgh at the end. We will finish the ride at Point State Park on Saturday, October 11, then we fly home from PIT the afternoon of the 12th. Because we’re doing a one-way ride, I’m trying to figure out (and I’m having difficulty) how to get cardboard bike boxes (e.g., the kind that manufacturers send to shops for their bike builds) on the Pittsburgh end so that we can put our bike on the airplane for our flight home. Plan A was to simply ship boxes from home (where I can easily source them), but I've since learned that will be very expensive ($250). I've recently reached out to Thick Bikes and Kindred Cycles, since they're relatively close to our planned downtown hotel - awaiting responses and maybe they'll be able to help me out (i.e. they'd save boxes, I'll pay a fee and pick them up). But since the date is approaching fast, I was wondering if others had suggestions. Any advice would be appreciated. Thanks!

Update: Here's a shout out to Kindred Cycles, Thick Bikes, and Golden Triangle Bike Rentals. I emailed these 3 bike shops in Pittsburgh and each promptly responded to confirm that they could save the 4 boxes that I needed. Following up to close the loop on this, in case anyone else ever needs to solve this problem. It was a relief to have the problem solved and a pleasant surprise to be able to arrange this so easily. Great people! As requested by one of the shops, in trade for the boxes I'll make a donation to the local bicycle advocacy group Bike Pittsburgh.