OK flew out last Thurs, sorry for the delay in reporting what happened but the hotels I stayed at had super super slow WiFi

The box with 2 paintings didnt fit the xray machine as I thought it wouldnt. I was told to walk thru and to leave the box leaning against the other machine and the TSA agent called for a manual scan. waited apx 10 mins before the other agent was able to take care of things. I was told to take the rope off it as he went to get some tape to reseal it. he opened the box enought to see all there were were the 2 paintings and he ran a swipe over the glass of 1 of the paintings. scaned the swipe and helped me reseal the box and off i went

No one said boo to me about boarding with box I was flying UA and board with group 1. As I entered the aircarft a 787-10 (never flew on any UA 787) i asked the FA at the door about placing it in a closest to which she answered sorry there are no closets on this aircraft, I asked about bIz class cabin, and she said I told you there are no closets at all on this plane and suggested I put it behind the last row of seats in coach. As I got to my row (Prem Econony- new seats) I pulled down the bin to put my carry-on in it and to my amazement the bin was Huge. i quickly put my carry-on down , picked up the box and was able by slanting it get it to fit in. Success!

Low and behold as some non-rev FAs boarded just before they were to close the door both of them pop open some closet doors to put their stuff into it, either of which would have held my box

Flight was 90 mins delayed taking off and after we were 1/2 way to LA I searched out the FA that lied to me and in front of the other FAs gave her a piece of my mind for lying to me. she was like a deer looking into oncoming headlights and tried to offer up some very lame excuse and a couple of the FAs told her dont make it any worse then you already have

any other aircraft but the 787-10 I hardly doubt the box would have fit into the bin, then again since its 2-3-2 and I was in the 2 seats and my row mate didnt have any carry-on it all worked out

I did get to EWR 2+ hrs before departure time just in case TSA denied me to take it as a carry-on

Thx to all who opined it all helped me get a Plan B and C into place just in case