# Why there is no airport IATA code XXX?

It seems that there is no XXX IATA code: from Wikipedia, XVL (Vinh Long, Vietnam) is followed by XYA (Yandina, Solomon Islands). There is a source claiming that XXX used to refer to Mena Intermountain Municipal Airport, but from Wikipedia this place seems (rather strangely) to have no IATA code at all (and a source for this claim is given).

What are the reasons for not having the XXX IATA code? Is this a reserved combination? Has it belonged to the Mena Airport in the past, and if so, why has it been deregistered on October 21, 2014, as the source claims?

• There are plenty of three-letter combinations that are not IATA airport codes. Why do you think XXX might be special? – Greg Hewgill May 17 '16 at 20:29
• I often refer to McCarren International Airport as XXX. – RockPaperLizard May 18 '16 at 0:30
• XXX looks like a placeholder. – Pyritie May 18 '16 at 8:58
• Based on the IATA site Pondlife linked in his answer, DDD, EEE, FFF, III, JJJ, NNN, OOO, QQQ, VVV, WWW, and ZZZ aren't currently assigned, so there's nothing special about 3-of-the-same-letter combinations being used, either. In all, there are 17,576 available 3 letter combinations, so it's not surprising that they haven't all been assigned. – FreeMan May 18 '16 at 12:16
• Also, if you look at the "Overview" panel of information at your source that claims it used to belong to Mena, you'll see that the end-date of the information is the day before the start date of the information. That's likely an indicator of invalid data. – FreeMan May 18 '16 at 12:18

## 1 Answer

It looks to me like the source site you quoted is unreliable or at least not current, e.g. it gives results for codes QQQ and ZZZ too, but they haven't been assigned by IATA. The actual IATA code for Mena (ICAO: KMEZ) seems to be MZX.

Anyway, there's no particular reason why XXX, ZZZ or any other specific combination should be assigned; they just haven't been used yet. There's also no reason why IATA should assign a code to every airport: the US alone has over 5,000 public airports but only 500 or so have air carrier service.

• If they're smart, XXX will never be assigned. It's an obvious placeholder for "no code", so there are probably a lot of systems and data out there that will get confused if it ever enters use (see: the experience of people with "NO PLATE" as their vanity license plate). – Mark May 18 '16 at 2:49
• @Mark Ah, the classic 'NULL' == NULL effect. – JAB Feb 28 '17 at 15:44