First recognize the phrase what goes up must come down. Well in the stock market the inverse is also true in stocks that are actively traded.
Now let me direct you to the chart at around the end of December 08 to January 2009. As you can see, the MACD line crossed where the red line went above the the green and then shortly thereafter crossed back. Right now you are seeing the first cross. When you see it cross back, you are too late.
The same happened at the end of March 2009 but was not significant and the volume was too low to flip!
Know how to read charts if you wish to make money flipping..... Good volume works well too but AERO has not had consistent volume to really flip it and make money. AERO is more a long term hold stock!