A lounge at BTA is not part of the picture, and before going further, a word of caution about the entity itself: available records for this small Cameroonian airfield are limited and not fully consistent on exactly which community it primarily serves, so treat specific claims about this particular field, beyond the honest absence of a lounge, with some caution and confirm directly with your airline if this leg matters to your trip.
What is clear is the broader pattern across Cameroon's smaller regional airfields: modest infrastructure, limited scheduled service, and no dedicated lounge or premium waiting space, since these fields are built for basic domestic connectivity rather than international or premium travel. Expect a small terminal building at most, without the seating, food and drink options, or gate infrastructure of a major airport like Douala or Yaounde.
Cameroon also carries real travel-advisory considerations worth a light check before you travel, particularly for movement outside the main coastal and central cities; several governments note region-specific cautions for parts of the country, so a quick look at your government's current advisory for Cameroon is a sensible step before finalizing any itinerary that includes a smaller regional field.
For the country's real airport and lounge picture, Yaounde Nsimalen International Airport (NSI) is the established anchor. As the gateway serving the capital, Yaounde, Nsimalen handles the bulk of Cameroon's international and premium-cabin traffic, alongside Douala's international airport on the coast, and any realistic lounge or business-facility access in this part of Cameroon runs through airports like these rather than a small regional field. If your trip includes both a regional leg and international travel, Nsimalen is where that connection, and any lounge access, becomes realistic.
Confirm current routing, this field's exact service area, and Nsimalen's lounge options directly with your airline before you travel, since records for smaller Cameroonian airfields are genuinely thinner than for the capital's main gateway.