Theme: Look! Up in the sky... - it' a bird. And bird related things start our theme entries.
1A. Sound from a tree : CHIRP. It's short and there is no symmetrical entry so we'll consider this a bonus.
20A. *Resolve once and for all : LAY TO REST
38A. *Savings for later in life : NEST EGG. Don't put all your eggs in one basket.
56A. Lyric in a Porter song that ends "Let's fall in love," and a hint to the starts of the starred answers (and 1-Across) : BIRDS DO IT. "Let's Do It, Let's Fall in Love" is a popular song(3:01) written in 1928 by Cole Porter. It was introduced in Porter's first Broadway success, the musical "Paris" (1928).
11D. *Like unreliable short-term businesses : FLY BY NIGHT. Don't put any of these eggs in yor basket.
27D. *Do some scheming : HATCH A PLOT
Argyle here. I hope you had your stars but they weren't really necessary. The unifier was pretty clear. It is similar to Kelly's puzzle , back in June. The grid even resembles a nest, especially if you highlight the theme entries. I picture CHIRP as the mama bird sitting on the edge of the nest.
Across:
6. Range between soprano and tenor : ALTO
10. Cpls.' underlings : PFCs
14. Flamboyant evangelist __ Semple McPherson : AIMEE. Clip(1:23) from an upcoming show at the 5th Avenue Theatre in Seattle.
15. Boston Bruins or Chicago Bears, e.g. : TEAM
16. Inter __: among others : ALIA
17. Baseball's Nolan and actress Meg : RYANs
18. Bath towel word : HERS
19. Natasha's no : "NYET!"
22. Many an October baby, astrologically : LIBRA
23. A __ alfa : AS IN. Phonetic alphabet spelling of Alpha.
24. Nairobi native : KENYAN. Map.
25. Satirical Mort : SAHL
28. Arrive after a tough trip : MAKE IT IN. Thru Kenya?
31. Schoolroom group : CLASS
33. Travelers' lodgings : INNS
34. Hypotheticals : IFS. No ifs, ands, or buts about it.
37. PC key : ALT
41. Miracle-__: garden brand : GRO
42. B'way setting : NYC
43. Slender woodwind : OBOE
44. Reacted to fireworks : OOHED
46. The Beatles' George : HARRISON
50. Salt Lake City college team, aptly : UTES
51. "Happy I can oblige" : GLAD TO
53. Cop's route : BEAT
55. Lassos : ROPES
61. "__ well that ends ..." : ALL'S. Shakespearean play.
62. Rani's garment : SARI
63. Cease-fire : TRUCE
64. Coagulate, as blood : CLOT
65. Treater's words : "ON ME"
66. Levels, as a building : RAZES
67. Italian noble family : ESTE
68. Fava or lima : BEAN
69. Illegally off-base GIs : AWOLs
Down:
1. Poet Sandburg : CARL
2. Breezy greeting : "HI YA"
3. "__ be wrong, but ..." : I MAY
4. Avis offerings : RENTALS
5. Cuban cash : PESOs
6. Zeus' daughter : ATHENA
7. Popular jeans : LEEs
8. Small fruit pie : TART
9. Mantric syllables : OMs. Ommm... Ommmm...
10. Italian sandwich : PANINI
12. Olds Cutlass model : CIERA
13. The devil : SATAN
21. Canyon edge : RIM
22. "Come on, we're late" : "LET'S GO"
24. Goal in checkers : KING
25. Read, as a bar code : SCAN
26. Treaty partner : ALLY
29. Flying toys : KITES
30. U-turn from WSW : ENE
32. Stable sounds : SNORTS. Pigs, horses...Farmer John up in the haymow.
35. Available for a date : FREE
36. Puts in a lawn the fast way : SODS
39. River of Spain : EBRO. OMG, it's a gimmee for me now. Map.
40. "... or __ thought" : SO I
45. Beat in a Western showdown : OUTDRAW
47. "__ Fideles": carol : ADESTE
48. Conan of "Conan" : O'BRIEN
49. Simpsons neighbor Flanders : NED
51. Pre-meal blessing : GRACE
52. Lounges around : LOLLS
54. Stars, in Latin : ASTRA. ASTRO is the common prefix.
56. Undoing : BANE
57. Cookbook writer Rombauer : IRMA. Her book.
58. Greek liqueur : OUZO. Better know what you're doing if you drink this stuff.
59. Its cap. is Reykjavik : ICEL.and
60. Tracy's Trueheart : TESS. Comic's Dick Tracy.
62. Cry out loud : SOB
Argyle