In 1993, Reno Air began offering low-cost flights from the Twin Cities to Reno Nevada. Northwest Airlines quickly responded by introducing cheaper fares on overlapping routes. Within months, Reno Air pulled out of the Twin Cities...and Northwest hiked its fares once again. Small airlines say that's an example of predatory pricing that Northwest and other large airlines use to stifle competition at their hub airports. The US Department of Transportation this week proposed a set of new rules that would penalize airlines for doing that. Mike Boyd is an airline industry analyst and head of the Boyd Group based in Colorado. He doesn't think the rules will make it any easier for small airlines to gain a toehold in markets like the Twin Cities.