We have an acrobatic theme, and are given the reveal immediately at 1-Down:
1-Down. With 57-Down, reverse ... and a hint to hidden letters in 6-, 9-, 15- and 21-Down : FLIP.
57-Down. See 1-Down : SIDE.
So it was no secret that we would be looking for the word "SIDE" appearing from the bottom-up. We are even given the theme locations right away. That took away from the fun of figuring it out on my own, but others may appreciate the leg up. Simple theme entries:
6-Down. Subject of debate : CONTESTED ISSUE.
9-Down. Retail promotion : STORE DISPLAY.
15-Down. Shipwreck movie staple : DESERTED ISLAND.
21-Down. General Electric co-founder : THOMAS EDISON.
Now, let's look at the rest.
Across
1. NFL threes : FGS. Field goals.
4. S&L offering : ACCT. 2 Abbr. to start...
8. Daisylike flower : ASTER.
13. Waikiki wreath : LEI.
14. Overwhelm in abundance : FLOOD.
16. Shoulder accessory : STOLE. At first, all I could think of was shoulder pads. Remember those from the '80s?
17. Place for the night : INN.
18. "Blue Sky" Oscar winner : LANGE. Jessica also won many other awards for her role.
19. Reliable : SOLID.
20. Wear a long face : POUT.
22. "Take __ a sign" : IT AS.
23. Geometric products : AREAS.
24. Having left the water : ASHORE.
26. '70s "Laugh-In" regular Ann : ELDER. I don't remember her.
28. Fat substitute : OLESTRA. It lost favor due to the side effects.
30. Panel with gauges : DASH.
33. Love interest : FLAME.
36. "Rosanna" band : TOTO. The video. 5:28
37. Empire founded by Manco Cápac, in legend : INCA. He was believed to be a fire and sun god.
38. Baltic capital : RIGA. Map.
39. Feints : DEKES.
40. Leave a lasting mark on : SCAR.
41. Energy measures : ERGS.
42. Picked out of a lineup : ID'ed.
43. Used : SPENT.
44. Throw down the gauntlet : DARE.
45. Barely enough : MINIMAL.
Followed by a semi-clecho:
47. Barely bests : EDGES.
49. Staid : SEDATE.
52. Bacall's love, informally : BOGIE. Listen here.
54. Ward of "Sisters" : SELA. I don't think I ever watched that show. She's the one at the upper left.
56. Some raised hands : YEAS.
58. Clear in class : ERASE.
59. __ about: recuperating : UP AND.
61. Pent- minus two : TRI-.
62. You might pass one in a race : BATON.
63. Choosing word : EENIE. meenie, miney, mo...
64. Like too many jokes : OLD.
65. Colleague of Ruth and Sonia : ELENA. Supreme Court Justices Bader Ginsburg, Sotomayor and Kagan.
66. Blissful place : EDEN.
67. Emmy-winning scientist : NYE. Bill Nye, the Science Guy.
Down
2. Italian port : GENOA.
3. Paranasal space : SINUS.
4. Gp. in a historic 1970 sports merger : AFL. The American Football League merged with the National Football League.
5. Actress Danes : CLAIRE.
7. Roman robe : TOGA.
8. Big name in Syrian politics : ASSAD. Bashar Al-Assad is the Syrian president.
10. Permissible variation : TOLERANCE.
11. Charles Lamb pen name : ELIA. "Essays of Elia."
12. Great American Ball Park team : REDS. The Cincinnati Reds, that is.
25. Bullfight cheer : OLE.
27. Thailand neighbor : LAOS.
29. Evidence of esteem? : TOKEN.
31. Do a cashier's job : SCAN. At our local supermarket, you can grab a wand on your way in and scan and bag your groceries as you go through the aisles. Thus totally eliminating the need for cashiers.
32. Roxie __, Zellweger's "Chicago" role : HART. The name on everyone's lips.
33. Barney's friend : FRED. The Flintstones. I was torn between Barney Rubble and Barney Fife, because "Andy" also fit.
34. Capital of Turkey : LIRA. The money type of capital, not the principle city.
35. Combined : AGGREGATE.
39. Old phone booth user's need : DIME. Good lord, I feel old!
43. __ sack : SAD.
46. Nasty sort : MEANIE.
48. Davis of "A League of Their Own" : GEENA. I loved her in that movie.
50. Wyoming's __ Range : TETON. Breathtaking.
51. Ahead of time : EARLY.
52. Tiny tot, in Toledo : BEBE. Good thing this was already filled by perps. My mind would have been on Tater Tots and Toledo, Ohio, I'm sure.
53. __ exam : ORAL.
55. Parrier's tool : EPEE.
60. Place to solve a puzzle : DEN. My go to places are the deck in summer, or the solarium in winter.
See you on the FLIP SIDE!
Marti