Air and au

In comparison to the other 10 spelling inconsistencies which I have listed at http://improvingenglishspelling.blogspot.com/2010/06/worst-irregularities-of-english.html and discussed in detail one by one, the irregularities of air and au are relatively minor.

The air-sound occurs in just 57 common words, 31 of which spell it with are or ‘open ar’ (Mary, malaria):
Bare, blare, care, dare, fare, flare, glare, hare, mare, pare, rare, scare, share, snare, spare, square, stare, ware. Area, aware, compare, declare, parent, prepare.
Hilarious, malaria, various, vegetarian.
Canary, Mary, wary.
     But nearly as many words spell it differently,
with only 15 using the easier-to-read air spelling:
Air, chair, fair, flair, hair, lair, pair, stairs,
dairy, prairie, affair, despair, éclair, repair, questionnaire.
Bear, pear, swear, wear, tear [tair /teer].
Aerial, aeroplane, aerobatics.
Heir, their/there, where.
     Despite the relatively small number of words with an air-sound, they cause quite a few reading and spelling difficulties. The their/there heterograph produces more spelling errors than any other English spelling irregularity, among children and adults alike. For some people this gets aggravated by they’re (the shortened version of ‘they are’).
     The redundant –e on the high frequency word ‘are’ complicates the decoding of the -are spelling in words like ‘care, dare, rare’ for beginning readers . They are also not helped by ‘there’ looking as if it should rhyme with ‘here’. The two pronunciations of ‘tear’ (teer and tair) cause difficulties too. (The main sound of ‘ear’ is ‘eer’, as in ‘ear, hear, near’, unlike ‘bear, pear’ etc.)
-----------------------------------------------------------
The au-sound has more exceptional spellings than air (39 au v 86 assorted different ones).
Its spelling is least predictable in the 53 words in which the au sound is followed by –l:
Haul/hall, maul, Paul;
All, ball, call, recall, fall, gall, pall, small, squall, stall, tall, wall.
Appal, install, instalment.
Bawl, brawl, crawl, drawl, scrawl, shawl, sprawl, trawl.
Almost, already, also, altogether, always.
Fault, vault.  Assault, somersault; cauldron, tarpaulin.
Altar, alter, (alternate, alternative), falter, halt, salt,
bald, scald, chalk stalk, talk, walnut, walrus, waltz.
poultry.

Before –t, the spellings are also random:
Astronaut, cosmonaut, nautical, taut,
Caught, daughter, haughty, naughty, slaughter, taught.
Bought, brought, fought, nought, ought, sought, thought.

The spellings of another 26 words with au
- auburn, auction, audible, August, authentic, author,
authorise, automatic, autonomy, autumn,
daub, gaudy, sauce, saucer, haunt, jaunt, launch, launder, staunch, taunt,
applause, cause, pause, Santa-Claus, exhaust, caution -
are made trickier by:
Awe, awful, awkward, awning, bawdy, dawdle, hawk, squawk,
broad.

As a final sound and before a final –n, the au-sound is consistently spelt aw:
Claw, draw, flaw, gnaw, jaw, saw, straw, thaw, law, paw, raw.
Brawn, dawn, drawn, fawn, lawn, pawn, prawn, sawn, spawn, yawn.
     This is problematic only for speakers of standard UK English in which au has the same sound as or.
For them, it worsens the unpredictable spellings of:
Bore, chore, core, fore, gore, more, ore, pore, score, shore, snore, sore, store, tore,
swore, wore.
For, nor, or.  
Door, floor, moor, poor.   
Four (fourth, fourteen, forty), pour, tour, your.   
Oar, boar, roar, soar.
War, warm, warn.