<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by MRW:
JFK SFO 1500 1825 DL1987 J7 D7 I7 Y7 B7 M7 H7 Q7 K7 L7#763*C
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What you saw is correct - those classes are all available - but might not be offered on the routing you want.
Here's an example... This availability shows "I7" - this is the deep-discount, usually non-ref Business fare (does earn 200% MQMs, tho). I don't think DL is offering I class service on the JFK-SFO route right now. However, you might have purchased an I ticket for say BRU-JFK-SFO a while ago (last "I" promotion in December?) and now want to change your ticket to this flight. DL would see that I is available, hit you with the $150 fee, and change you on to this flight. But you couldn't call DL and purchase an I-class ticket for JFK-SFO.
Seeing all those low fares avail is a very good indication that you'll be able to get a low fare ticket, but it's never 100% certain.