It is #EnigMarch and when dared to design a puzzle, I still make space in my schedule.
Across:
1. Runway pavement
7. Get new loan from S&L, perhaps
11. Who might sell you a pedigree pup
13. Makes equal
15. Deadlock
16. Mattress maker
17. Salt-and-pepper look, but for horses
18. Wrapped-and-draped clothing
20. Roman ruler, e.g., Romulus
21. Not wet
22. Standard encumberance state used in discussing the airspeed velocity of a swallow
23. Before
24. Genetic strand
25. Beau Geste author
27. Vim and _____
30. Ebony and _____
31. Concurred
33. Body of water
34. One in Oaxaca
35. Salt, Geneva, Silver, Placid, and Ricki
37. IRL periodical
40. Thick woolen cloth used for outer clothing.
41. "I agree with this prayer"
42. Tastiest part of a cotton plant if you're a weevil
43. Neptune's oyster fork
45. Civilian military, ideally well-regulated
47. Touch or smell
48. Dog breed popular with hunters and perhaps C programmers
49. Ownership document
50. Upcoming Dwayne "The Rock" Johnson Christmas action movie
Down
1. Old Ford auto
2. Protective clothing
3. Make good on a debt
4. Average
5. They pay for your "free" websites
6. Maker of small airplanes
7. How new doctors learn how hospitals work
8. Really big-scale sci-fi MMORPG
9. First female vice-presidential nominee representing a major American political party: Geraldine _______
10. Number that doesn't need a decimal point
12. Number that might or might not need a decimal point
14. State of Germany which I assume was famous for having sacks on sacks on sacks of coins or something
19. Sharp knock
22. They Might Be Giants song: (I was thinking of an) _________ Thing
24. Surname when you don't know the name
26. Between Pa. and Ky. in the USA
27. Secure storage places
28. Paid no attention
29. High school freshman year
32. Oroville or Three Gorges
33. Elder
36. AFL player, Bob Dole's running mate, Housing Secretary Jack ____
37. "You have to go out, but you don't have to come back," for example
38. Sigourney Weaver horror flick
39. Harsh light
42. Tie up tightly
44. Stupid
46. Sir Mix-a-Lot can't do it
ROT13'd explanation and answer and an upside-down solution grid:
Guvf pebffjbeq hfrf n tvzzvpx: QRA svgf va n fdhner.
Npebff: 1. GNEZNP, 7. ERSV, 11. OERRQRE, 13. RIRAF, 15. VZCNFFR, 16. FREGN, 17. EBNA, 18. FNEV, 20. ERK, 21. QEL, 22. HAYN(QRA), 23. NTB, 24. QAN, 25. CPJERA, 27. IVTBE, 30. VIBEL, 31. NTERRQ, 33. FRN, 34. HAN, 35. YNXRF, 37. ZNT, 40. YB(QRA), 41. NZRA, 42. OBYY, 43. GEV(QRA)G, 45. ZVYVGVN, 47. FRAFR, 48. CBVAGRE, 49. QRRQ, 50. ERQBAR.
Qbja: 1. GOVEQ, 2. NEZBE, 3. ERCNL, 4. ZRNA, 5. NQF, 6. PRFFAN, 7. ERFV(QRA)PVRF, 8. RIR, 9. SREENEB, 10. VAGRTRE, 12. ERNY, 14. FNKBAL, 19. ENC, 22. HAERYNGRQ, 24. QBR, 26. JIN, 27. INHYGF, 28. VTABERQ, 29. TEN(QRA)VAR, 32. QNZ, 33. FRAVBE, 36. XRZC, 37. ZBGGB, 38. NYVRA, 39. TYNER, 42. OVAQ, 44. (QRA)FR, 46. YVR.
Gur pvepyrq tevq fdhnerf fcryy bhg PB(QRA)NZR, PBQR ANZR