According to my chainsaw math, and applying the appropriate scope language, by YE 2015 UAX will have 240 70/76 seat aircraft (from the January 22, 2015 fleet plan below, in bold are the 70/76 seater numbers) and the limit is 255. January 1, 2016 it can go up to 325 ONLY if a new small narrow body aircraft is added to mainline. There is also a bunch of other ratio language to get to that 325 relating to 50 seaters being parked, etc. but that's the basic limit.

January 22, 2015 UAL fleet plan:

Fleet Plan
As of January 22, 2015, the Company’s fleet plan was as follows:
YE 2014 23 74 14 51 94
YE 2015 21 74 25 51 81
FY ∆
(2) - 11 - (13)
B747-400
B777-200
B787-8/9
B767-300/400
B757-200/300
B737-700/800/900 283 A319/A320 152
Total Mainline Aircraft 691
YE 2014 Q400 28
308 25 152 - 712 21
YE 2015 FY ∆ 20 (8)
Q300 55- Q200 1616-
ERJ-145 ERJ-135 CRJ200 CRJ700 EMB 120 EMB 170 EMB 175
Total Regional Aircraft
245 192 (53) 9 - (9) 68 50 (18)
115 100 (15) 9 - (9)
38 38 -
33 82 49
566 503 (63)

UPA section 1-C-1-g:

1-C-1-g Number of 76-Seat Aircraft
If the Company adds New Small Narrowbody aircraft to the Company Fleet, then on or after January 1, 2016, the number of permitted 76-Seat Aircraft may increase from 153 (as permitted under Section 1-C-1-a-(2)-(c)) up to a total of 223 76-Seat Aircraft, and the number of permitted 76/70-Seat Aircraft may increase from 255 (as permitted under Section 1-C-1-a-(2)-(c)) up to a total of 325 76/70-Seat Aircraft, except that once the number of 76/70-Seat Aircraft exceeds 255, then the number of 70-Seat Aircraft may not be more than 102. 76-Seat Aircraft (above 153 such Aircraft) may be added on a one 76- Seat Aircraft for each one and one quarter New Small Narrowbody Aircraft (1:1.25) ratio (rounded to the closest integer). In addition, in the event more than 153 76-Seat Aircraft are in United Express Flying, the Company shall remove from United Express Flying a number of 50-Seat Aircraft determined as follows:
1. “FSFC” is the number of 50-Seat Aircraft in United Express Flying on the date that the 154th 76-Seat Aircraft enters United Express Flying.
2. Subtract 125 from FSFC.
3. Divide the number resulting from step 2 by seventy (70). This results in a factor “X”
rounded to the second decimal place.
Page 4
4. For each 76-Seat Aircraft added to United Express Flying above 153, remove from United Express Flying a number of 50-Seat Aircraft no less than X, with the resulting number of 50-Seat Aircraft to be removed, rounded to the closest integer.
5. Example 1: If the number of 50-Seat Aircraft in United Express Flying is 334, then FSFC-125 equals 209; when 209 is divided by seventy (70), then X = 2.99
6. Example 2: If the number of 50-Seat Aircraft in United Express Flying is 488, then FSFC-125 equals 363; when 363 is divided by seventy (70), then X = 5.19.
For the phrase “rounded to the closest integer,” in step 4, the values .1 to .4 shall be rounded down to the next lower whole number and the values .5 to .9 shall be rounded up to the next higher whole number.
1-C-1-g-(1) If on January 1, 2016, or any succeeding January 1 thereafter, the number of 50-Seat Aircraft in United Express Flying exceeds the maximum permitted number, the Company shall require United Express Carriers that engage in United Express Flying to suspend or cease operations on a sufficient number of 50-Seat Aircraft or 76-Seat Aircraft to comply with these requirements within sixty (60) days and to remain in compliance thereafter. The Company shall be excused from compliance with the provisions of this Section 1-C-1-g-(1) in the event a Circumstance Beyond the Company’s Control is the cause of such non-compliance