So, I've always thought I knew my civil aircraft pretty well, but here I am, sitting in the LGA RCC, when this airplane pushes back from gate C6: it's clearly a 737 of the post-300 vintage, but it has massive wing fences (at least 8 feet). It belongs to ATA, registration N302TZ. First correct answer entitles respondent to a beer, at a time/place TBD. Bonus points will be awarded for a link to where I can read up on this weirdness...