Theme: Various kinds of drops - The last word in the theme entries can be backed with DROP.
17A. Stuffy room need : FRESH AIR. Airdrop - Getting supplies in without actually landing.
21A. Smith, to Abigail Adams : MAIDEN NAME. Name-Drop - Claim to know famous people. Abigail was the wife of John Adams.
33A. Mello Yello rival : MOUNTAIN DEW. Dewdrop - A bead of water that forms overnight on blades of grass, if the humidity is high enough. Also the name, Dew Drop Inn; a bar of my ute.
42A. Door-controlling sensor : ELECTRIC EYE. Eye Drop - Used to try to hide the redness after staying too long at the Dew Drop.
54A. 1984 Prince hit : PURPLE RAIN. Rain Drop. The song seems to have a vigorous copyright defense. No clip of the original.
62A. Painted setting behind stage actors, or what the ends of 17-, 21-, 33-, 42- and 54-Across can literally have : BACKDROP
Argyle here. Not as tough as yesterday's but probably some can find some nits.
Across:
1. Curtain hanger : ROD
4. Exec's "Now!" : ASAP. "As Soon As Possible" but they really want sooner than possible.
8. Works for People, perhaps : EDITS. People Magazine.
13. '50s political slogan name : IKE. Dwight David "Ike" Eisenhower: "I Like Ike"
14. "Because Freedom Can't Protect Itself" gp. : ACLU. (American Civil Liberties Union)
15. Dead Sea discovery : SCROLL. Ancient text found in caves.
19. Overly affected : TOO TOO
20. Cab ride cost : FARE
23. UFO navigators, so they say : ETs
25. One-one, for one : TIE
26. Messy type : SLOB
27. In and of itself : PER SE
30. Tip holder : JAR
31. Me, to Matisse : MOI. or to Miss Piggy.
32. Language of Southeast Asia : LAO
38. Recipient of much Apr. mail : IRS
39. Baby seal : PUP
40. Overnight stopping place : INN. Do drop in for the night. And 48A. 40-Across postings : RATES
41. Anger : IRE
45. Like very familiar jokes : OLD
46. Acidity nos. : PHs. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. Pure water has a pH very close to 7. - Wikipedia
47. Road crew goo : TAR
50. Resort near Ventura : OJAI
52. Spanish month : MES. No particular month, just the word for month.
53. El Al home: Abbr. : ISRael
57. Purina rival : IAMS. Pet food manufacturers.
61. Error-removal aid : ERASER
64. DVD player error message : [NO DISC]
65. Lago filler : AGUA. Water in a Spanish lake.
66. Bustle : ADO
67. Uses Avis, say : RENTS
68. Put in order : SORT
69. Kentucky Derby action : BET
Down:
1. Repeated musical accompaniment : RIFF. JzB, what say you?
3. XING sign critter : DEER
4. "That's the spot" : AAH
5. Takes for a ride : SCAMS
6. Et __: and others : ALIA
7. 17th-century New England settler : PURITAN
8. First name in makeup : ESTÉE Lauder.
9. Anti-rodent brand : D-CON
10. Attaches, as patches : IRONS ON
11. Complete dolt : TOTAL IDIOT
12. Like many NFL replays : SLO-MO
16. Pop singer Lisa : LOEB
18. Dates : SEES
22. More in need of cleaning : DIRTIER
24. Entices : TEMPTS
27. Ballet bend : PLIE
28. Viscount's superior : EARL
29. Traditional New Year's Day procession : ROSE PARADE
30. Planet with the most moons : JUPITER
31. Gold rush figures : MINERS
34. Your and my : OUR
35. Unspecified number : ANY
36. Author Gardner : ERLE. Best known for the Perry Mason series.
37. Gets married : WEDS
43. Contributes for a joint gift : CHIPS IN for the married couple.
44. Melons with wrinkly rinds : CASABAs
49. Very dry : ARID
50. Start serving customers : [OPEN]
51. Courtroom panelist : JUROR
52. Former Ford autos, briefly : MERCs. (usual Mercury Grand Marquis)
53. Acquire, as debts : INCUR
55. For fear that : LEST
56. Shakespearean villain : IAGO. A character in Othello.
58. Many a Syrian : ARAB
59. Airplane __: cellphone setting : MODE. Wiki
60. Parking space : SPOT
63. "Krazy" comics feline : KAT. A fine note to end on.
Argyle