How do you find out how many seats are available on a flight
 

Just curious, I've the impression that you guys somehow know how many seats are available in C class and how many seats are available in D class, e.t.c.

How do you guys know?? Is there a website where I can look for such things?

There are a number of tools available to do this, one of which is this:

http://www.flyaow.com/classual.htm

So MAN Flyer if I am doing a search and come up with the following under Cabin Class: C9 D9 Z9 Y9 B9 M9 H9 Q9 V9 W9 S9, what does it mean? Sorry for asking such an amateur question.

The example you show means there is full availability in all classes. When a 'class' is sold out the number next to the letter will be '0', and smaller numbers means there is a limited amount still available etc.

What MANFlyer said, plus in case you don't already know: First Class (F,A), Raffles Class (Z, C, D), Economy (Y all letters displayed after Y).

Just to add to what Manflyer and StarG said

when it shows F9 A9 C9 D9 J9 Y9 M9 and all that, it means
that the airlines is willing to sell you at least 9 seats in those classes.

Note that the numbers can't be added up - F9 A9 doesn't necessarily mean you can book 18 first class seats. It doesn't work that way.

As a general rule of thumb from observation at our company travel agent (who have terminals in my office)- most airlines show different "max" numbers when the flight is wide open i.e fairly light.

SQ for example shows a "max number" of 4 for first and business, 9 for economy.
UA shows a max of 9 all classes
TG F - 2, C-2, Y-9
MH F -4, C- 4, Y-9
NZ C-4 (IIRC), Y-7
OS- C-9, Y-9

Just some observations can't think of more off the top of my head and i think this could be different from system to system. My TA uses Abacus.

What the others said....and here's my 2 cents.

If you're trying to find out availability for SQ flights, a lot of the availability tools out there will give you a general idea, but not the accurate results you'd get with availability on say, UA or AA.

For example, if you use the KVS Availability Tool, you could get 2 different results for the same flight (example below, where the first was a lookup using the ITN/CWT engine and the second using the ITN/UA engine.

SQ 63 BKK 11:15 SIN 14:40 773 0 F4 A4 C4 J4 D0 Y0 B0 M0 W0 Q0 N0 V0 P4 H0 K0 Z9

SQ 63 BKK 11:15 SIN 14:40 773 0 F4 P4 A4 Z4 C3 J0 D0 S0 Y4 E0 B0 M0 W0 H4 Q0 N0 T0 V0 L0 K4

The general idea you'd get from these results is that economy is almost sold out, business is selling fast (no more discounted D seats available) and first is wide open.

However, if you went down to an SQ CTO, you could see a totally different availability on their screens. It makes a difference where you're making the booking - if you're booking an SQ flight through UA, you'd look up the availability in the ITN/UA tool....if you're booking direct with SQ, you'd have to check their availability with an agent.

P.S. I could be wrong about this, but an SQ agent told me that different SQ CTOs would show different availability for the same flight depending on point-of-sale restrictions. Don't know how that works.

I get the general idea. Thank you all very much for your input.

AFAIK there can be restrictions within a booking class, eg different availability based on where purchased, whether journey is point to point or through to other destination, codeshare or under code of the carrier, etc.

There is a thread on the *A forum showing the booking classes for *A carriers.