How to brush paint Testors small enamels to look it was airbrushed ??

Two bushes? Man, that's Spartan modeling! lol.

Generally, the best way to brush-paint is to thin the paint and apply two or three thin coats, rather than to glob on paint in one thick coat. And a wide, thick brush of GOOD QUALITY is best for this.

However, I would ask you HOW did your airbrush "break"? Most problems with "broken" airbrushes can be solved with a thorough cleaningl. You might want to investigate that before you waste the time and effort doing an impossible task.

Doog is right. Keep your paint thin and do several cotes. Use your small angled brush for dry brushing the color transitions to get a feathered edge between colors and go slowly. If you rush it, it will not look like anything but a bad brush job.

"Softly, softly, catchy monkey"

You'd be better off using a rattle-can and masking tape. To get a feathered edge with a spray can, leave the edge off the surface by folding one edge of the tape over (about an eighth-inch works)... If it's a "mottled" effect you're after, then take a round brush, cut the bristles back to about an eighth-inch in length, and use a stabbing/stippling motion to apply the paint.

Dip the brush into the paint left on the inside of the LID and then stab a piece of paper with it until it's similar to the amount used fir dry-brushing...

You can also use that technique to go th length of the color demarcation line... It won't look sprayed, but it's as close as you're gonna get without spraying...