http://en.wikipedia.org/wiki/Availability_heuristic
"The availability heuristic is a mental shortcut that relies on immediate examples that come to mind. The availability heuristic operates on the notion that if something can be recalled, it must be important.Subsequently, people tend to heavily weigh their judgments toward more recent information, making new opinions biased toward that latest news "
The fact you noticed oil going down does not mean you should buy airlines, that is a perfect example of the availability heuristic. Overweight the importance of the move in oil because you happened to notice the move.
You guys talking all this nonsense on individual stocks should really learn the 101 basics of behavioral finance. It doesn't sound like you have any strategy, just random data points and then falling prey to the availability heuristic on what you happened to have ran into data wise. Although, that does sum up retail trading in general.
http://www.amazon.com/Judgment-unde...414248472&sr=8-2&keywords=bias+and+heuristics