CO has planes that are grounded so they could add more if they wanted to, but they won't. Why should they? If the planes are full there is a better chance that they are profitable. Carriers want their planes to be mostly full, not 60% full where everyone has an empty middle seat next to them.
There are several options from JFK-LAS nonstop but no others from EWR:
[KVS Availability Tool 3.4.0/Platinum - Amadeus: Timetable/NL-BCDF]
Code:
NYC New York Metro NY US = JFK LGA
LAS Las Vegas Mccarran Int'l NV US [KLAS]
SAT 04 Jul 2009 - 11 Jul 2009
Carrier Flight From Depart To Arrive A/C St Frequency | Dur'n | Dep T | Arr T | Effect | Ending | Exceptions
--------- ------ ---- --------- ---- --------- ---- ---- ----------------------------------------------------------------
CO 768 EWR 07:35 LAS 09:47 EQV 0 -----67 05:12 C 1 04 Jul 11 Jul
CO 768 EWR 07:35 LAS 09:57 753 0 12345-- 05:22 C 1 06 Jul 24 Jul
B6 187 JFK 07:55 LAS 10:24 320 0 1234567 05:29 5 1 15 Jun 08 Sep
DL 727 JFK 08:20 LAS 10:59 73H 0 ----5-7 05:39 3 1 28 Jun 16 Aug
DL 727 JFK 08:20 LAS 11:00 757 0 1234-6- 05:40 3 1 24 Jun 31 Mar
CO 568 EWR 09:00 LAS 11:28 753 0 -----67 05:28 C 1 04 Jul 11 Jul
CO 568 EWR 09:00 LAS 11:38 753 0 12345-- 05:38 C 1 06 Jul 24 Jul
VX 251 JFK 09:10 LAS 11:50 320 0 1234567 05:40 4 1 25 May 07 Sep
DL 729 JFK 09:30 LAS 12:02 73H 0 12345-7 05:32 3 1 04 Jun 31 Mar
B6 197 JFK 10:18 LAS 12:45 320 0 1234567 05:27 5 1 15 Jun 08 Sep
CO 668 EWR 13:00 LAS 15:15 739 0 1234567 05:15 C 1 02 Jul 30 Jul
B6 711 JFK 14:45 LAS 17:28 320 0 1234567 05:43 5 1 15 Jun 08 Sep
CO 1468 EWR 15:29 LAS 17:53 739 0 -----6- 05:24 C 1 04 Jul 25 Jul
CO 1468 EWR 15:29 LAS 18:03 739 0 12345-7 05:34 C 1 05 Jul 10 Jul
DL 163 JFK 16:45 LAS 19:46 73H 0 123-567 06:01 3 1 03 Jul 13 Jul
DL 163 JFK 16:45 LAS 19:47 757 0 ---4--- 06:02 3 1 02 Jul 13 Aug
AA 257 JFK 16:50 LAS 19:35 757 0 1234567 05:45 8 1 11 Jun 24 Aug
CO 268 EWR 17:25 LAS 19:50 739 0 -----6- 05:25 C 1 04 Jul 25 Jul
CO 268 EWR 17:29 LAS 20:04 739 0 12345-7 05:35 C 1 05 Jul 10 Jul
B6 191 JFK 18:35 LAS 21:25 320 0 1234567 05:50 5 1 15 Jun 08 Sep
CO 468 EWR 19:35 LAS 22:20 738 0 -----6- 05:45 C 1 04 Jul 25 Jul
CO 468 EWR 19:35 LAS 22:30 753 0 12345-7 05:55 C 1 05 Jul 10 Jul
CO 868 EWR 20:10 LAS 23:11 738 0 ---45-7 06:01 C 1 05 Jul 10 Jul
B6 199 JFK 20:17 LAS 23:04 320 0 -23---- 05:47 5 1 17 Jun 08 Sep
DL 733 JFK 21:00 LAS 00:03 +1 757 0 1234567 06:03 3 1 01 Jul 17 Aug
B6 199 JFK 21:45 LAS 00:28 +1 320 0 1--45-7 05:43 5 1 18 Jun 07 Sep