Here is certain way to obtain thrust by using small wings in circulating closed system air conditions like these on the picture (red arrow is indicated the air flow way). This system is powered by two air compressors (signed on this scheme as "8"s) accelerating the air each in opposite direction creating a small air vortex. All is contained in a rounded tube with parallel arms. On upper side is vertical cutaway and, below is horizontal cutaway. Theoretically, the thrust in this case should occur as a result of differences in air pressure - more pressure under wings and less pressure on upper side of wing like in standard used air vehicles, however real pressure forces in this case can in reality be against each other so there may be no greater result force or turbulent flowing will disturb required laminar flow so the system won't work on proper efficiency, but on this stage of this project I can't recognize eventual mistakes nor predict if it's correct. As usually all I try to do is only to magnify and signify the probability of existence various different from standards sometimes propulsion methods what is important for this civilization cause this civilization have only one low effective mean of transport in space and generally this is rocket based propulsion. I've also considered a H. Coanda's effect in closed air system situation solutions recently but maybe It is pretty weird situation that nobody doesn't never notice or try to solve until today nor even consider this kind of problems in practical ways. Are there existing real and solid disadvantages making the whole technical problem useless for practical applications, I don't know, but if there are some possibilities that this solution can work correctly somehow I will get know about that.