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I'm sure it has nothing to do with the Q drop, but FWIW, in a lot of peoples' minds, "BTK" stands for that horrible serial killer who operated near Wichita KS for several years and was later brought to justice from his own hubris.

https://en.wikipedia.org/wiki/Dennis_Rader

Some other BTKs. [Number 11 could be the airline you referred to in your post which is thought to have been in Russia. Also note that the Bulgarian communications has a Cyrillic character which transliterates to a K in Number 6]:

1) Genetic:
https://en.wikipedia.org/wiki/Bruton%27s_tyrosine_kinase

Bruton's tyrosine kinase (abbreviated Btk or BTK) also known as tyrosine-protein kinase BTK is an enzyme that in humans is encoded by the BTK gene. BTK is a kinase that plays a crucial role in B-cell development.

2) Stock Market - BioTechIndex
https://finance.yahoo.com/quote/%5EBTK

3) Building systems
https://btk.com

4) Sports - Body Train Kit
http://www.btksport.com

5) Bacterial toxin:
Bacillus thuringiensis kurstaki - a pesticide https://oehha.ca.gov/media/downloads/pesticides/fact-sheet/hqadipel110917.pdf

6)Bulgarian Communications -
The Bulgarian Telecommunications Company, abbreviated as БТК in Cyrillic and sometimes transliterated as BTK https://en.wikipedia.org/wiki/BTK

7) WWII era dive bomber
https://en.wikipedia.org/wiki/Kaiser-Fleetwings_XBTK

8) Railroad
https://en.wikipedia.org/wiki/Baku–Tbilisi–Kars_railway,

9) Political in Kiribati:
https://en.wikipedia.org/wiki/Pillars_of_Truth

Pillars of Truth (Boutokaan Te Koaua) is a political party in Kiribati. The party was created through a split in the National Progressive Party, which was the first party to rule after Independence in 1979.

10) Turkish Communications
Turkish: Bilgi Teknolojileri ve İletişim Kurumu (BTK)), is a national telecommunications regulatory and inspection authority of Turkey. It was formerly known as the Telecommunications Authority (Turkish: Telekomünikasyon Kurumu (TK)).

https://en.wikipedia.org/wiki/Information_and_Communication_Technologies_Authority_(Turkey)

11) Batik Air
https://en.wikipedia.org/wiki/Batik_Air

Lion Air, the parent company of Batik Air, created Batik Air as a full-service airline which began operations in May 2013 using Boeing 737-900ERs leased from Lion Air. Batik Air's 737-900ERs were fitted with two-class seating, replacing Lion Air's one-class 737-900ER service. Batik Air provides a personal television (in-flight entertainment system) in every seat, light snacks and free meals, seat pitches of 32 inches (81 cm) for economy class and 45 inches (114 cm) for business class, and a free baggage allowance of 20 kg (44 lb) for economy class and 30 kg (66 lb) for business class. In mid-2012, Lion Air signed a commitment with Boeing for five 787 Dreamliners for Batik Air, intending to have them delivered by 2015. Lion Air later cancelled this deal and temporarily shelved its plans for the long-haul expansion of Batik Air.[1][3][4][5]

12) Music - several
Birth Through Knowledge, a Canadian hip-hop/rock band best known for the 1998 single "Poppycock"
"Bind Torture Kill", a song by the band Suffocation on its self-titled album
Bind, Torture, Kill, an album by the band Suicide Commando
Doom Metal band Church of Misery released a track called "B.T.K" about Rader on their album Thy Kingdom Scum
Thrash Metal band Exodus released a track called "BTK"

13) Physics:
Blonder Tinkham Klapwijk, surnames of the three physicists who wrote a theory describing electrical transport across an interface between a non-superconducting metal and a superconducting one, based on the concept of Andreev reflection

Probably not exhaustive, but as much as I want to do today on it! :-D