Narrative:

We were level at 10000 ft MSL, ZFW cleared our flight aircraft X to 15000 ft. We read back the clearance to climb to 15000 ft. As we were climbing through 11000 ft, ATC asked us to say our altitude. We told him and he said 'you took flight aircraft Y's climb clearance, level at 12000 ft.' 5 or so mins later, ATC cleared us to climb to FL210. Our company aircraft, flight aircraft Y queried the controller to see if the climb clearance was for aircraft Y or aircraft X. The controller, realizing his mistake, told us aircraft X not to climb and then correctly issued aircraft Y's climb clearance to FL210. We were only filed to 16000 ft for cruise. Twice we received incorrect climb clrncs from the controllers. The problem for both pilots and controllers is that airlines have way too many similar flight numbers scheduled to operate in the same airspace each day. With a hub and spoke operation, closely numbered flts to and from a city pass each other in the same airspace causing confusion for controllers and pilots. I have always been amazed at the lack of thought put into designating flight numbers of aircraft operating at the same time on the same frequencys.

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Original NASA ASRS Text

Title: A FLC FLEW A CLRNC INTENDED FOR ANOTHER COMPANY ACFT NEAR SPS.

Narrative: WE WERE LEVEL AT 10000 FT MSL, ZFW CLRED OUR FLT ACFT X TO 15000 FT. WE READ BACK THE CLRNC TO CLB TO 15000 FT. AS WE WERE CLBING THROUGH 11000 FT, ATC ASKED US TO SAY OUR ALT. WE TOLD HIM AND HE SAID 'YOU TOOK FLT ACFT Y'S CLB CLRNC, LEVEL AT 12000 FT.' 5 OR SO MINS LATER, ATC CLRED US TO CLB TO FL210. OUR COMPANY ACFT, FLT ACFT Y QUERIED THE CTLR TO SEE IF THE CLB CLRNC WAS FOR ACFT Y OR ACFT X. THE CTLR, REALIZING HIS MISTAKE, TOLD US ACFT X NOT TO CLB AND THEN CORRECTLY ISSUED ACFT Y'S CLB CLRNC TO FL210. WE WERE ONLY FILED TO 16000 FT FOR CRUISE. TWICE WE RECEIVED INCORRECT CLB CLRNCS FROM THE CTLRS. THE PROB FOR BOTH PLTS AND CTLRS IS THAT AIRLINES HAVE WAY TOO MANY SIMILAR FLT NUMBERS SCHEDULED TO OPERATE IN THE SAME AIRSPACE EACH DAY. WITH A HUB AND SPOKE OP, CLOSELY NUMBERED FLTS TO AND FROM A CITY PASS EACH OTHER IN THE SAME AIRSPACE CAUSING CONFUSION FOR CTLRS AND PLTS. I HAVE ALWAYS BEEN AMAZED AT THE LACK OF THOUGHT PUT INTO DESIGNATING FLT NUMBERS OF ACFT OPERATING AT THE SAME TIME ON THE SAME FREQS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.