Protoavis (Triassic)

The Triassic (Protoavis) came before the Jurassic (Archeopteryx)... so if this is a true bird, then Archie is no longer the world's "oldest bird". It would also mean that birds did not evolve from dinosaurs.

Protoavis: A Revolution in Bird Evolution?
"The paleontologist Sankar Chatterjee has recently described the fossil Protoavis, from Late Triassic deposits in Texas. Chatterjee claims that Protoavis is a true bird that is actually closer to modern birds than Archaeopteryx. If this is true, this would push the origin of birds back by about 80 million years. It would also show that the first birds lived at the same time as the earliest dinosaurs -- which could disprove or force modification of the standard hypothesis that birds are descended from the highly derived coelurosaurian dinosaurs, which are not known from the Triassic. This would require major rewriting of the evolutionary history of the birds and dinosaurs alike."
(Source)

Hope they discover more fossils and confirm what this creature was, but by now... these dino-bird people are so fixed on their dogma that no matter what fossil evidence is produced they will try to deny the evidence.

An article focusing on genetic research T-Rex/Birds.

"...Putting more meat on the theory that dinosaurs' closest living relatives are modern-day birds, molecular analysis of a shred of 68-million-year-old Tyrannosaurus rex protein -- along with that of 21 modern species..."

Oh... they merely wanted to estimate the "closest living relative" and were never implying that T-Rex evolved into chickens. But the dinosaur-bird crowd interpreted the data as they wanted to.

"...-- confirms that dinosaurs share common ancestry with chickens, ostriches, and to a lesser extent, alligators."

Molecular Analysis Confirms Tyrannosaurus Rex's Evolutionary Link To Birds (Source)

Nobody would deny that dinosaurs share "common ancestry" with birds, but who would presume birds, "...evolved from..." dinosaurs like T-Rex?

The kind of people who paint bright red feathers on large solitary predators.

Protoavis. One artist's depiction.

Mark Hallett (paleontological art) depiction of Protoavis.

The fossil

Theories about flight:

"Debates about the origin of bird flight are almost as old as the idea that birds evolved from dinosaurs, which arose soon after the discovery of Archaeopteryx in 1862. Two theories have dominated most of the discussion since then: the cursorial ("from the ground up") theory proposes that birds evolved from small, fast predators that ran on the ground; the arboreal ("from the trees down") theory proposes that powered flight evolved from unpowered gliding by arboreal (tree-climbing) animals. A more recent theory, "wing-assisted incline running" (WAIR), is a variant of the cursorial theory and proposes that wings developed their aerodynamic functions as a result of the need to run quickly up very steep slopes, for example to escape from predators."
(Source)

No matter which may be true, the underlying driving force of why they were compelled to fly, and achieved it, may be explained in this bit of research. Their ancestors from the Triassic and even earlier,

Swimming led to flying

"...Like a fish paddles its pectoral fins to swim through water, flying insects use the same physics laws to "paddle" through the air, say Cornell physicists."
(Source)

..through instinct, perhaps even epigenetics... swimming prompted birds to fly.

I found a nice upload that discusses "ProtoAvis" and two competing theories for how birds (flight) came to be. I am in the third camp with only minimal variations on the how's and why's... 3. Aquatic bird theory:

"The idea that all modern birds stem from an aquatic ancestor might come as a surprise, admits Chiappe. "If you look at the evolutionary tree of living birds, the most primitive are all land birds — ratites, ostrich, emu, pheasants," he says. "It seems that many lineages left the water and colonized the land." But although many people think of ducks, geese and other waterfowl as specialized animals, they are quite primitive in comparison to highly evolved species such as songbirds, Chiappe points out. What's more, almost every bird group alive today has representatives that live in or around water, Chiappe says, suggesting that a watery lifestyle may be an ancient tradition that has persisted in many lineages. Pelicans are not closely related to penguins; and neither bears a close kinship with herons, he adds."
(Source)

Again, it should be pointed out, that the "bright blue" feathers used to portray Protoavis, are highly unlikely to have existed during the Triassic. Our feathered friends had a very limited array of pigment,

"...The broad palette of feather colours displayed by birds serves diverse biological functions, including communication and camouflage. Fossil feathers provide evidence that some avian colours, like black and brown melanins, have existed for at least 160 million years (Myr), but no traces of bright carotenoid pigments in ancient feathers have been reported." (Source)

If Protoavis is indeed, truly a bird, and hopefully with more fossils, in time we will know. But if in the case that it is, Protoavis will push back known bird origins into the Triassic. This would be devastating to the "theropod dinosaur to bird" hypothesis, because the earliest "theropod dinosaurs" themselves, arose during the Triassic.

To provide some perspective on the time-frame I am attaching the bird graph which shows some of the birds of the fossil record in contrast to the Cretaceous dinosaurs, who arose at a much later time and yet, are mistakenly credited as being the "ancestors" of birds.