The patrol bought the plane in December with money from a fund designated for purchases of motor vehicles, boats and aircraft.
Senators gave first-round approval Tuesday to a bill requiring the patrol to seek legislative approval for any future purchases out of the fund of more than $100,000. The measure also would allow the fund to be tapped for vehicle maintenance.
Republican Sen. Brad Lager, of Savannah, says the plane's purchase has shaken the Legislature's trust in the patrol.
Last month, the Missouri House passed a measure making the new plane's flight logs a public record. The Senate bill needs one more vote before moving to the House.