What's going on here? (says R3Y takeoff)
 

The chase plane suggests this is some sort of test -- for what?
Flying boats didn't ordinarily take off like that, did they?

Convair R3Y Tradewind - reminds me of the over rotation/minimum speed unstick tests performed by airliners, presumably similar tests were flown (or not) 70 years ago?

Other aircraft looks like an A-1E Skyraider...

Looks very similar to a video and photos I've seen of the Martin PBM fitted with RATO. Maybe ditto being tested on the Tradewind ?

DRUK,either that or `a bit late on the flare,Hoskins`.....

Once did that in my school swimming pool - still bear the mental scars... :}

The description on Flickr does say takeoff, so I'll go with the overrotation suggestion. With those four props blowing across the wing, it appears to be a candidate for a steep Vx climb profile.

That chase plane has got too far ahead to record it becoming airborne. My hunch is it's tests of a water landing, miscaptioned.

The Catalina, which had no flaps, was able to do a landing at a very high angle of attack, close to the stall, in rough seas. Perhaps a test of a simlar technique?

Looks like rough water testing. The F2Y Sea Dart (part of the same strategic seaplane force programme that spawned the Tradewind) went through a programme of taxiing in progressively bigger seas to determine the operating limits, and I'd imagine the R3Y was subject to something similar. Whether this is a landing, an attempted takeoff or simply a very heavy pitching during high speed taxiing I'm not sure.

Quite an interesting programme. There was a bomber (the Martin Seamaster), a fighter (the Convair Sea Dart) and a transport (the Tradewind) intended to operate as a unit out of remote bays as a mobile strategic deterrent just like SSBN submarines. It would be supported by repurposed escort carriers, converted cruisers or submarines. It was overtaken by Polaris but there was a period when the Strategic Seaplane Force was regarded as the more viable solution.

Sounds like the latest US Marine plan to disperse assets over the E Pacific