What you can do is click no every time the warning appears.
However the best thing to do is to add this to your fs9.cfg.
Paste these into your [FrameCallNoWarn] section:
~van=1
A320=1
A340=1
AT72=1
B1=1
B206=1
B52=1
B707=1
B727=1
B737=1
B744=1
B767=1
BA46=1
BE10=1
BE18=1
BE35=1
BE55=1
C130=1
C152=1
C172=1
C182=1
C188=1
C5=1
CAR=1
CONC=1
CSL=1
D8100run=1
DC10=1
DC3=1
DC4=1
DC9=1
DH8B=1
DHC2=1
DHC6=1
F14=1
F4=1
F5=1
ffg7=1
FORD_POS=1
G21=1
J3=1
LJ45=1
M113=1
Master CSL=1
OHP=1
P28A=1
P28R=1
P32R=1
P51=1
Pa28r180=1
SAIL=1
SF34=1
SH33=1
ST75=1
STS=1
T37=1
TOBA=1
TUG=1
Tug1=1
TWR=1
U2=1
UH1=1
UH1D=1
UH60=1
ULT=1
VAN=1
XSR=1
Hope this helps!